I work as a waitress part-time in MA. The owner states that the government now assumes that waitresses make 20% in tips for each table served. Of course this is not always the case, but I always thought the tip amount is 15%. Do I have to claim more than 15% for taxes? The owner says that they can't prove it for cash tips, but credit cards, he has to put whatever is written on the receipt? Is this so?

Thanks

If there is some written record for the tips, that is what the owner must report.

Otherwise, a standard tip formula is used. 20% seems a bit high, but I believe the IRS standard is 18%, so it is not TOO high.