I've had IT now for about 2 years, and after using various techniques to deal with decimals, I have found the best one that works for me.
I used my macro program to set up a macro. I have IT set on 2 spaces after periods and colons. If I want to use the period as a decimal or the colon in a time value, I press the CONTROL key as I hit the period or decimal key. All the macro does is go back the 2 spaces, so quickly I hardly notice it. I've gotten quite used to hitting another key along with the period or colon in these situations - second nature now.