Why does self-employed retirement deduction screen show a maximum allowable contribution of $26,000 to a 401(k) plan?

I am 52 and married with 1099-NEC work and an individual 401(k). 
 While it appears I may have contributed too much in profit-sharing contributions, I am confused by the maximum allowable contribution screen showing $26,000.  If I continue to the Your Retirement Contributions screen, I see Individual 401(k) of $27,000, and Profit Sharing Plan of $37,000.  Once I pay, I will see the calculations that explain the amount to withdraw; however, this should be removed from profit sharing, and I expect I should be allowed to contribute $27,000 to the individual 401(k).  The review screen states the maximum deferral is $27,000, but the preceeding screen states $26,000 for some reason.  What could I be misunderstanding?