I did some testing and I'm pretty sure that the values are getting rounded upwards (in steps of 0.5?)
config.cpp: http://pastebin.com/YyhfqTHT
(see the config.cpp for reference to what I'm saying below)
It happens with ALL dropdown menus but let's say the 'type' dropdown menus:
Type8 (@ line 64) has value = 0.55 - If i select that in the attributes and save & re-open the attributes window, it will return with type0, aka value = 0.95
If I however select type10, which has value = 0.45 - it will return with type9, aka value = 0.50
The rounding to type9 happens with type11,14,12,13 and even type9 itself.
Anything above value = 0.50 is rounded to the highest value, in this case to value = 0.95 ("Manually Add")