Passing parameter as arguments in G65

I have a Milltronics RH35 and a Marposs probe that uses macros to run probing cycles. I can't seem to figure out how to pass parameters on a G65 line. For example this will run just fine:

Code:

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G65 P9312 H1.D2.S1. K-.35.

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This however will not:

Code:

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G65 P9312 H1. D[P1] S1. K-.35.

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According to the documentation on my controller this is the proper syntax for parametric programming and it work fine with any other G code such as:

Code:

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G00 X[P1]

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or even

Code:

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S[P1]

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or

Code:

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F[P1]

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.

I have many other programs that use interactive parameter in this manner and none of them have this problem. I've been banging my head against the wall because I don't understand why it doesn't work.