Box 5 on the SSA-1099 form is the total benefit minus any repaid benefits. Medicare premiums have not been deducted, so they should not be added to this total to arrive at the amount totaled in line 1 of the worksheet.
No, there isn't a problem with the Social Security Benefits Worksheet in TurboTax. The Medicare premiums on lines C, D, and E are not added into line 1. Line 1 is just line A plus line F. (Line 1 says "Add amounts from line A and line F," not "line A through line F.") If you don't have an RRB-1099, line 1 is equal to the amount in SSA-1099 box 5. Nothing is added.
When you enter your SSA1099 into the software, just enter it exactly as it appears. You do not need to do anything with that worksheet on the back of the form. The software will do all of the calculations for you.