I was thinking a 25% SEP plan works out to 20% but that may just be for self-employed? Anyway, in trying to verify that, I discovered I may have allowed a client to put too much money into his IRA's--I thought you could contribute to your SEP and an IRA as well. This is correct; however, your total contributions cannot exceed the SEP IRA contribution limits.
IRA's are trickier than many folks think. I had a client who would tell me about his Traditional IRA contributions--one year I mentioned Roth's and he said, oh I put $6,000 in my Roth as well but I didn't think I needed to tell you about that. He had been putting the limit into both types for years, what a mess to straighten out. Then the year after he retired, he was still putting money into his IRA... geez