In 2.08, this is the way monthly budget figures can be entered. Enter your budget figures this way for now and an updated version of NV2 will address this issue. It will not be in the 2.09 release but perhaps a service pack or 2.10.
In NV1, dividing the annual budget amount by twelve was nice if you had to allocate the same monthly total but tedious if it was not divisible by twelve. Currently, all users are in the same boat when entering their budget figures.
A better method will be added to NV2 in an upcoming release.