I sometimes work 10 games on a weekend (2 Fri night and 4 each on Sat and Sun) and I have had weeks in which I have also worked 1 or 2 games a night Mon thru Thu, so I guess it's not incredibly unusual for me to work up to 18 games in a week, although it only happens once or twice in a season.
I did work a MS tournament two years ago in which I worked 15 games on a Fri night, Sat and Sun (3 on Fri night, 6 each on Sat and Sun). I required them to pay me a med allowance.
Disclaimer - some of the MS games are shorter than NF rules, i.e.: 6 or 7 minute quarters or running clock, but a lot of them are standard 8 minute quarters.