Feodor, I am aware of this issue of the script, but it not really that important for two reasons. First, most tempdb databases are smaller than 4 GB. And two, even if they are larger than 4 GB, realizing that contention is happening in the initial allocation pages is enough information to know that you have a problem. It is kind of like taking the pulse of a person. While knowing the pulse doesn't give you the entire picture of somebody's health, it still is enough information to know if there is a potential problem or not.
Brad M. McGehee
DBA