So I noticed a few bugs. I didn't see these mentioned anywhere...

Firstly in the Item Pickup tab, for "Increase Counter Max" and "Increase Amount", it doesn't let you put in a value higher than 32767 while the max for a counter is 65535. I noticed that this is almost exactly half of what the max counter too. The box "But not above" however allows you to go up to 65535 just fine. It may prevent you with other boxes too, but I haven't tested all of them out.

Second, for some reason around 30,000 on a counter with String Control Codes, it seems that ZC doesn't count properly. I had a counter that was at 30,000, and had the String set via string control codes to change when that counter was at 35,000. Upon activating the string, it changed even though the counter was at 30,000 and not 35,000. I continued to test and 40,000, 45,000, 50,000 and 60,000 values also changed even though the counter was at 30,000 and not the proper values.

I have a feeling these two bugs are related but I'm not positive.

I don't know how many people use counters on such a high value, but it'd be very nice to be able to use this for my Bank.

This is all in the ZC 2.5 Stable Windows build.