Meltingplot PLA: raise slow_down_layer_time by calibration factor 1.5

Print feedback on CHX 350 with a 0.8 nozzle at 0.44 mm layer height showed
curling at the retraction points with the derived value of 25 s. There is no
cooling headroom left to trade: fdm_filament_pla pins fan_min_speed =
fan_max_speed = 100, and additional_cooling_fan_speed is inert because no
Meltingplot machine enables auxiliary_fan. Minimum layer time is the only
remaining lever; 35 s prints cleanly at that geometry.

The cross-section rule only fixes the ratios between nozzle sizes, so this
is a calibration of the PLA anchor itself: both PLA ladders are scaled by
1.5 (Extrudr 9/20/38/56/83 s, Meltingplot PLA 8/17/30/45/66 s for
0.4/0.6/0.8/1.0/1.2). The Extrudr base fan_cooling_layer_time goes 60 -> 100
so the 1.2-nozzle value stays below it.

Other materials are left unchanged - only the PLA anchor has a real
counter-example so far.

resources/profiles/Meltingplot/filament/Extrudr PLA NX2 Matt @0.4 nozzle.json

@@ -9,7 +9,7 @@
 		"10"
 	],
 	"slow_down_layer_time": [
-		"6"
+		"9"
 	],
 	"compatible_printers": [
 		"Meltingplot MBL 133 0.4 nozzle",

resources/profiles/Meltingplot/filament/Extrudr PLA NX2 Matt @0.6 nozzle.json

@@ -9,7 +9,7 @@
 		"15"
 	],
 	"slow_down_layer_time": [
-		"13"
+		"20"
 	],
 	"compatible_printers": [
 		"Meltingplot MBL 133 0.6 nozzle",

resources/profiles/Meltingplot/filament/Extrudr PLA NX2 Matt @0.8 nozzle.json

@@ -9,7 +9,7 @@
 		"20"
 	],
 	"slow_down_layer_time": [
-		"25"
+		"38"
 	],
 	"compatible_printers": [
 		"Meltingplot MBL 133 0.8 nozzle",

resources/profiles/Meltingplot/filament/Extrudr PLA NX2 Matt @1.0 nozzle.json

@@ -9,7 +9,7 @@
 		"25"
 	],
 	"slow_down_layer_time": [
-		"37"
+		"56"
 	],
 	"compatible_printers": [
 		"Meltingplot MBL 133 1.0 nozzle",

resources/profiles/Meltingplot/filament/Extrudr PLA NX2 Matt.json

@@ -37,10 +37,10 @@
 		"25%"
 	],
 	"fan_cooling_layer_time": [
-		"60"
+		"100"
 	],
 	"slow_down_layer_time": [
-		"55"
+		"83"
 	],
 	"cool_plate_temp": [
 		"60"

resources/profiles/Meltingplot/filament/Meltingplot PLA @0.4 nozzle.json

@@ -9,7 +9,7 @@
 		"11"
 	],
 	"slow_down_layer_time": [
-		"5"
+		"8"
 	],
 	"compatible_printers": [
 		"Meltingplot MBL 133 0.4 nozzle",

resources/profiles/Meltingplot/filament/Meltingplot PLA @0.6 nozzle.json

@@ -9,7 +9,7 @@
 		"16"
 	],
 	"slow_down_layer_time": [
-		"11"
+		"17"
 	],
 	"compatible_printers": [
 		"Meltingplot MBL 133 0.6 nozzle",

resources/profiles/Meltingplot/filament/Meltingplot PLA @0.8 nozzle.json

@@ -9,7 +9,7 @@
 		"22"
 	],
 	"slow_down_layer_time": [
-		"20"
+		"30"
 	],
 	"compatible_printers": [
 		"Meltingplot MBL 133 0.8 nozzle",

resources/profiles/Meltingplot/filament/Meltingplot PLA @1.0 nozzle.json

@@ -9,7 +9,7 @@
 		"27"
 	],
 	"slow_down_layer_time": [
-		"30"
+		"45"
 	],
 	"compatible_printers": [
 		"Meltingplot MBL 133 1.0 nozzle",

resources/profiles/Meltingplot/filament/Meltingplot PLA.json

@@ -22,7 +22,7 @@
 		"#F8F8F8"
 	],
 	"slow_down_layer_time": [
-		"44"
+		"66"
 	],
 	"slow_down_min_speed": [
 		"15"