I just did a quick test on this.
I put a value of 5 (for no particular reason) in variables #50, #99, #100, and #110.
I restarted Mach4, #50 and #99 still maintained their value of 5. #100 and #110 returned to a NIL.
When I am using #VARS I tend to start at #200.
I was doing some testing on my desk computer a few months ago and was using #VARS #200-#215, these still have their values from when I was testing our Grinding Program.