That's not really comparing apples to apples. Unlike a covered call, you aren't actually in possession of the shares with a spread. First you are assigned (so you are short the shares) and then you exercise your long to acquire shares. That is a multi-step process. In the covered call situation, you are assigned, your shares are taken, and you're flat. End of story.
I sold covered calls for well over a year on stocks that paid monthly dividends (ERF, O, PGH). Once a month I would sell the front month call (usually slightly OTM, or infrequently one strike ITM if I thought it would move against me).
If the option was ITM at expiration, I got assigned. Normally I got the dividend. Some times people called me out ahead of time, in which case they got the dividend, but that dividend didn't come from me, it came from the company. There wasn't a single time that I paid the dividend.