Correct. If you marked that box on TurboTax's 1099-R form in agreement with the marking on the Forms 1099-R provided by the payers, the amounts are being reported on the correct lines. Apparently your annuity is an IRA annuity required to be reported on lines 4a/4b. The 401(k) distributions are considered to be pension distributions (not IRA distributions), so they go on lines 5a/5b.
