diff --git a/src/libslic3r/calib.cpp b/src/libslic3r/calib.cpp
index 0ba04478f9..dc2952d502 100644
--- a/src/libslic3r/calib.cpp
+++ b/src/libslic3r/calib.cpp
@@ -21,7 +21,7 @@ namespace Slic3r {
     }
 
     std::string convert_number_to_string(double num) {
-        auto sNumber = std::to_string(value);
+        auto sNumber = std::to_string(num);
         sNumber.erase(sNumber.find_last_not_of('0') + 1, std::string::npos);
         sNumber.erase(sNumber.find_last_not_of('.') + 1, std::string::npos);
 
@@ -33,7 +33,7 @@ namespace Slic3r {
         std::stringstream gcode;
         const double lw = 0.48;
         Flow line_flow = Flow(lw, 0.2, m_nozzle_diameter);
-        const double len = m_digit_len;
+        const double len = m_digit_segment_len;
         const double gap = lw / 2.0;
 
         /* 
@@ -280,8 +280,7 @@ namespace Slic3r {
     std::string calib_pressure_advance_pattern::generate_test(double start_pa, double end_pa, double step_pa) {
         BoundingBoxf bed_ext = get_extents(mp_gcodegen->config().printable_area.values);
         
-        bool is_delta = is_delta();
-        if (is_delta) {
+        if (is_delta()) {
             delta_scale_bed_ext(bed_ext);
         }
 
@@ -317,7 +316,7 @@ namespace Slic3r {
         auto start_x = center_x - (object_size_x + pattern_shift) / 2;
         auto start_y = center_y - object_size_y / 2;
 
-        if (is_delta) {
+        if (is_delta()) {
             delta_modify_start(start_x, start_y, num_patterns);
         }
 
@@ -348,36 +347,36 @@ namespace Slic3r {
             line_width_anchor()
     }
 
-    double max_numbering_height(double start_pa, double step_pa, int count) {
-        int max_length = 0;
+    double max_numbering_height(double start_pa, double step_pa, int num_patterns) {
+        int most_characters = 0;
 
-        for (int i = 0; i < count; i += 2) {
+        // note: only every other number is printed
+        for (int i = 0; i < num_patterns; i += 2) {
             std::string sNumber = convert_number_to_string(start_pa + (i * step_pa));
 
-            if (sNumber.length > max_length) { max_length = sNumber.length; }
+            if (sNumber.length > most_characters) { most_characters = sNumber.length; }
         }
 
-        max_length = std::min(max_characters, m_max_number_length);
+        most_characters = std::min(most_characters, m_max_number_length);
 
-        return (max_length * m_digit_len) + ((max_length - 1) * m_number_spacing);
+        return (most_characters * m_digit_segment_len) + ((most_characters - 1) * m_number_spacing);
     }
 
     double get_distance(double cur_x, double cur_y, double to_x, double to_y) {
         return std::hypot((to_x - cur_x), (to_y - cur_y));
     }
 
-    std::string draw_line(double to_x, double to_y, double line_width, double layer_height, std::string comment = std::string()) {
+    std::string draw_line(double to_x, double to_y, std::string comment = std::string()) {
         std::stringstream gcode;
         auto& config = mp_gcodegen.config();
         auto& writer = mp_gcodegen.writer();
 
-        Flow line_flow = Flow(line_width, layer_height, m_nozzle_diameter);
+        Flow line_flow = Flow(line_width(), m_height_layer, m_nozzle_diameter);
         const double filament_area = M_PI * std::pow(config.filament_diameter.value / 2, 2);
-        const double e_per_mm = line_flow.mm3_per_mm() / filament_area * config.print_flow_ratio;
+        const double e_per_mm = line_flow.mm3_per_mm() / filament_area * m_extrusion_multiplier;
 
         Point last_pos = mp_gcodegen.last_pos();
         const double length = get_distance(last_pos.x(), last_pos.y(), to_x, to_y);
-        
         auto dE = e_per_mm * length;
 
         if (comment.empty()) {
diff --git a/src/libslic3r/calib.hpp b/src/libslic3r/calib.hpp
index aeb99e21e3..2e6e3a28c6 100644
--- a/src/libslic3r/calib.hpp
+++ b/src/libslic3r/calib.hpp
@@ -47,7 +47,7 @@ private:
     void delta_modify_start(double start_x, double start_y, int count);
 private:
     GCode* mp_gcodegen;
-    double m_digit_len {2};
+    double m_digit_segment_len {2};
     double m_nozzle_diameter;
     int m_max_number_length {5};
     double m_number_spacing {3.0};
@@ -85,27 +85,30 @@ class calib_pressure_advance_pattern: public calib_pressure_advance
 
         std::string generate_test(double start_pa = 0, double end_pa = 0.08, double step_pa = 0.005);
 
-        double to_radians(double degrees) { return degrees * (M_PI / 180); }
+        double to_radians(double degrees) { return degrees * M_PI / 180; }
         
         double line_width() { return m_nozzle_diameter * m_line_ratio / 100; };
         double line_width_anchor() { return m_nozzle_diameter * m_anchor_layer_line_ratio / 100; };
         
         // from slic3r documentation: spacing = extrusion_width - layer_height * (1 - PI/4)
-        double line_spacing() { return line_width() - mp_gcodegen->config().layer_height.value * (1 - M_PI / 4); };
-        double line_spacing_anchor() { return line_width_anchor() - mp_gcodegen->config().initial_layer_print_height.value * (1 - M_PI / 4); };
+        double line_spacing() { return line_width() - m_height_layer * (1 - M_PI / 4); };
+        double line_spacing_anchor() { return line_width_anchor() - m_height_first_layer * (1 - M_PI / 4); };
         double line_spacing_angle() { return line_spacing() / std::sin(to_radians(m_corner_angle) / 2); };
 
         double object_size_x(int num_patterns);
         double object_size_y(double start_pa, double step_pa, int num_patterns);
 
-        double max_numbering_height();
+        double max_numbering_height(double start_pa, double step_pa, int num_patterns);
 
         double get_distance(double cur_x, double cur_y, double to_x, double to_y);
-        std::string draw_line(double to_x, double to_y, double line_width, double layer_height, std::string comment = std::string());
+        std::string draw_line(double to_x, double to_y, std::string comment = std::string());
     private:
         int m_anchor_layer_line_ratio {140};
         int m_anchor_perimeters {4};
         int m_corner_angle {90};
+        double m_extrusion_multiplier {0.98};
+        double m_height_first_layer {0.25};
+        double m_height_layer {0.2};
         double m_glyph_padding_horizontal {1};
         double m_glyph_padding_vertical {1};
         double m_line_ratio {112.5};