I know taxes vary by state, so if anyone from Pennsylvania happens to know anything about this, I would greatly appreciate any info you can provide.  Our venue charges the price pp, a 21% service charge, and 6% PA sales tax.  
I was under the impression that this meant the following:
$10,000 total venue cost (this is just an example)
+ $2,100 (service charge)
+ $600 (tax)
------------------
$12,700
The coordinator at the venue is telling us this:
$10,000 total venue cost
+ $2,100 (service charge)
------------------
$12,100
+ $726 (tax)
------------------
$12,826
I was under the impression that the service charge would not be taxable, but our coordinator is telling me that it is.  I know the $126 difference in my example isn't really all that much of a difference, but there is quite a difference when I run the numbers for the actual costs.  If she's right, that's fine.  We have no problem paying it.  I just want to know if she's trying to screw us out of several hundred dollars.