numbers

Hello,
I wonder if you could explain why it’s in the plural.
<From the start, the Bush administration miscalculated the numbers of troops needed…>

If it were “the number of troops”, would it be a mistake ?
Thank you.

I guess you can go either way -- I prefer just plain "number" in this sentence. Maybe it's different in Canada, UK, NZ, etc.

Most likely because there were more than just one number of troops.

If you need one number for infantry
another number for support
another for special ops
then you have "numbers of troops" and not a number of troops

Thanks, guys.