Yes, this seems to make sense based on the following calculations:
- $20,000 x 15.3% self-employment tax = $3,060
- $40,000 x 15.3% self-employment tax = $6,120
In addition your income is subject to income tax. Say you are in the 15% tax bracket, that's an additional $6,000 for the additional income. This totals $12,120 before any business deductions or credits.
In regards to the state, your income jumped $20,000 which likely changed your tax bracket and therefore, you owe more.
Your original projections seem low and your actual figures seem accurate.
