Nothing has changed except for increases in contribution limits. Even the TurboTax self-employed retirement section remains unchanged. You must have done something wrong. There is no situation where TurboTax would calculate your maximum self-employed retirement deduction for any type of self-employed retirement plan to be exactly 25% of net income from self employment with net income from self employment in the range that you have.
I suggest comparing the Keogh, SEP and SIMPLE Contribution Worksheet between your 2017 and 2018 tax returns.
