Thanks for the answers @Kirk. Yes, adding math expressions would open you up to having to handle a lot of corner cases: What does it mean to add 64123 to NaN in the context of Photomechanic and what do you do with divide by zero. I thought I would check.
I got a bit excited finding the actuations property. I ran for many many years using LR's sequence value. I will probably be just as happy with PM's since it sounds like it works the same way.
<snip> or it wraps around to zero.<snip>
How big can that number get before it wraps? 16 bit int, 32 bit int?