Excel 2007 : Why would SUM(range) function not add ".5"

I'm trying to add a row of 7 cells. When I use the =SUM(C32:I32) formula I don't get the correct answer. It's not adding one of the cells which has a value of .5

If I use =SUM(C32+D32+E32+F32+G32+H32+I32) it adds it all up just fine.

All cell formatting is General. The first formula will add the decimal if it's greater than 1. So it will add up 1.5 but not .5

Some additional info that may help is that the ".5" is not actually entered. That value is calculated from a VLOOKUP formula. If I delete the formula and simply type in .5 the original formula works but Excel adds a preceding "0" in front of the decimal. "0.5" is what is actually displayed. I don't want this because there are a ton of numbers on the worksheet and I need it as simple and uncluttered as I can get it. If the second formula works with just .5 then at least I know the ".5" is recognized as a number and doesn't need the preceeding zero. Why does individual cell addition differ from range addition???

I'm sure this is a very elementary problem, but for the life of me I can't figure it out.