Both forms are exactly the same thing. I think that a speaker may subconsciously feel that adding unnecessary verbiage like “going to” gives the listener time to prepare for the most likely words to follow.

The phrase “go ahead and…” is the least commonly used unnecessary phrase in English. I’ve heard these things already on a DIY show: go ahead measure the boards. Now go ahead and cut it. Is it a good time to sand your dog? ” “Leave out that phrase and no information is lost?

Can you possibly not understand how “empty” phrases make a speech “funny”?