Conditional formatting time in minutes glitch?

[SunTrader]

For Excel 2007 -

I've got a worksheet with over a thousand filled cells with time 1:30 PM style (this might not matter I suppose?). It has a "start-time" of sorts of 6:00 PM and advances a minute at a time thereafter.

A check-cell, that I manually adjust, applies conditional formatting to the sheet based on this cell's time value. Everything works fine ... until it gets to 6:00 PM, 6:26 PM, 6:44 PM and I suppose many other minute times further down the timeline. I've tried changing the layout as well as of course using another worksheet but no luck. I've used both +Time(0,1,0) added directly in each cell or adding same but by way of referencing a master step cell. Always the same result.

I think I vaguely remember reading something a while back off a google search about this phenomenon but no workable solution??? Not sure?

Appreciate any assistance.

 

[SunTrader]

Another thing I tried this morning is to separate out times from dates of both columns by using:

int(G2) in a new column for date only, then subtract that from original column to be left with just the time.

Then I tried again countif to both new time only columns (column P and S) countif($P$2:$P100,S2) and got it to work.

So I am set. Thanks none the less.