There are a few thousand people using the probing and auto zero macros in my 2010 Screenset, and as far as I know, they run the same on everyone's machine's. I think some of what Terry is saying depends on the complexity of the macros, and what specific things the macro is doing.
I haven't run into any issues.
Now, if you're not using the parallel port, then all bets are off. When using motion controllers, probing is handled by the device's plugin, and they don't all work the same.

The look ahead is only for CV. But it does increase the depth of the que.  Don;t readd to much into any of this . IF you plann for the worst case senario and MOST do then most PCs will be able to run the code. But if you need to optimize the code for speed you have to pay close attention.  In a simple probe solution say a Center of Circle routine a couple of sec WAIT is not a big deal. BUT in a 3d Z probing routine repeating those 2-3 secs of wait can add HOURS to the completed routine.

(;-) TP