It asked me how much pension I wanted to split and I put in $15,000. It added that to my income (the lower income) but didn't deduct it from my husband's, so now our total income is higher!
The deduction on his return happens after the total income line. To see this, click on the review tab and select Bottom line tax summaries. On this page, click Detailed tax summary. When you scroll down, you can see the deduction at line 210.