I did something exactly like that with instance variables (I named the variable "frame") rather than comparing frame numbers
The ">=" is because double clicking can increase the variable faster than the software can react.
This was a while ago (Very early effort with C2) and I don't recall why I chose that method, nor do I recall why I chose "tap" over "touch" - but it works perfectly so it may work for you.
I hope that helps!