Did you mean "simple" as in easy? Or, SIMPLE as in SIMPLE IRA plan? Any retirement plan through their company has a plan document which tells you the terms of matching. For instance, SIMPLE IRA might be 3% match (not more than this, and not exceeding the $ limit, of course). The software you are using doesn't know the employer's plan details.

You can read here:

https://www.irs.gov/retirement-plans/plan-participant-employee/retirement-topics-simple-ira-contribu...

And here is a limit calculator that gives you Solo 401(k), SIMPLE IRA and SEP IRA $ limit calculations:

https://www.pacificlife.com/home/insights/calculators/self-employed-retirement-plan-maximum-contribu...