I am fairly new to Cimplicity and I am struggling to figure out how to reference a timer or counter DONE bit. I just recently figured out that the offset field is actually used for bit locations, which complicates things.

I'm clueless.

First off the Cimplicity that you reference has nothing to do with a specific PLC, it is 'PLC Programming' or 'HMI' or 'SCADA' software, which do you have?
What driver are you using if not PLC Programming and if you are programming a PLC then which one do you have?
In the GE Fanuc PLC world the timers do not need a 'Done' bit if they have one it is assigned by the programmer so you will need documentation to know what it is. It 'may' be any valid discrete reference address so again we need to know which PLC to know what the valid addresses are.
Sorry to confuse things but that's the way it is.

With the old direct device driver, "T4:0.DN". Simple as that. The other method is to call it "T4:0.CTL" and use the bit number. Search the help for "CTL" or "DN". It will tell you exactly how AB counters and timers map into Cimplicity PE's nomenclature.

With OPC, all bets are off. I made it a practice a long time ago not to reference timers this way so I have no idea what you call it for that.

the DONE bit is 13 and the ENABLE is 15. I'm not sure of the timing (TT) bit.