Over-ride IPM In Mach3

[dpaish]

Greetings,
When executing a post or cutting sequence, as the Syil X4 CNC Mill is cutting I can over-ride the spindle speed, but can not over-ride the Feed Rate. Is the ipm locked in Mach3 during a cutting sequence?

I have seen videos that you can increase of decrease the feed rate as it is cutting, but mine will not change. The bar goes up and down and the over ride light blinks, but that is it.

My mach 3 version is R4.042.029

Here is a copy of a simple program that does not work..

G00 G49 G40.1 G17 G80 G50 G90
G20
(2 1/2 Axis Profiling)
M6 T3
M03 S1500
G01 X0.3121 Y1.1096 Z0.1250 F15.0
Z-0.2800 F10.0
X0.4312 Y1.1100 F1.0
X0.4444 Y1.1093
X0.5171 Y1.1013
X0.5341 Y1.0970
X0.6017 Y1.0747
X0.6169 Y1.0673
X0.6779 Y1.0323
X0.6908 Y1.0225
X0.7439 Y0.9764
X0.7544 Y0.9646
X0.7981 Y0.9089
X0.8062 Y0.8955
X0.8391 Y0.8318
X0.8446 Y0.8169
X0.8653 Y0.7467
X0.8679 Y0.7308
X0.8750 Y0.6518
Y0.1372
X0.8717 Y0.0976
X0.8692 Y0.0817
X0.8569 Y0.0407
X0.8505 Y0.0262
X0.8345 Y-0.0040
X0.8256 Y-0.0169
X0.8044 Y-0.0432
X0.7931 Y-0.0543
X0.7674 Y-0.0762
X0.7538 Y-0.0851
X0.7241 Y-0.1017
X0.7085 Y-0.1080
X0.6755 Y-0.1185
X0.6583 Y-0.1215
X0.6187 Y-0.1250
X0.1313
X0.0917 Y-0.1215
X0.0745 Y-0.1185
X0.0336 Y-0.1051
X0.0184 Y-0.0978
X-0.0108 Y-0.0809
X-0.0237 Y-0.0711
X-0.0490 Y-0.0489
X-0.0595 Y-0.0372
X-0.0803 Y-0.0106
X-0.0884 Y0.0029
X-0.1039 Y0.0333
X-0.1094 Y0.0482
X-0.1192 Y0.0817
X-0.1217 Y0.0976
X-0.1250 Y0.1372
Y0.6518
X-0.1179 Y0.7308
X-0.1153 Y0.7467
X-0.0921 Y0.8244
X-0.0857 Y0.8389
X-0.0524 Y0.9023
X-0.0435 Y0.9152
X0.0006 Y0.9707
X0.0119 Y0.9817
X0.0655 Y1.0276
X0.0790 Y1.0365
X0.1406 Y1.0713
X0.1562 Y1.0775
X0.2243 Y1.0994
X0.2415 Y1.1025
X0.3121 Y1.1096
Z0.1250 F15.0
M5 M9
M30