If you're looking at preferred parking (SSc4.3) for and you determine that your project needs 4.15 LEV parking spaces, how many should you provide, 4 or 5? While this is a relatively harmless difference (one more sign probably won't break the bank), the difference between 1 or 2 showers (SSc4.2) might be more of an issue in an small office building.
I wasn't sure about this answer until I noticed that the credit templates solved the answer for me. One tenth of a shower is a full shower, and rounding up, even when the numbers would typically be rounded down is the norm.
Take the following example:
5% of 180 FTE is 9.00000 secure bicycle storage spaces require. If we add one more FTE, then 5% of 181 is 9.05, which in most minds would round down to 9. In this case however, the LEED credit calculator rounds the number up to 10 required spaces: