That's why I suggested you pic up the data from the second to last pass. With a low horsepower spindle the overrun will be less since the tap will act as a brake. With a high HP machine it's more a function of VFD braking ability.
Yes, that is what makes me worry about how well this function could work, because it is unknown how much more friction will the extra depth add, I mean it is not sure that the friction adds up linear with the passes.
How does peck work if the Q number is not an even division of the hole depth? Does it correct on the last pass or spread it out over the number of passes.
The endpoint is always what you program, no matter if Q is an integer fraction of the full depth or not, the peck algorithm always finishes with the programmed Z depth.
If the Q is not an integer fraction of the total depth then the last peck will be shorter and that's all, it will still finish at the programmed Z.