I was just in terminal A this evening and walked past the bus stop. I asked the Delta person working the desk there. She said the bus runs about every 15-20 minutes and takes about 7-10 minutes to ride. There are two entry points - at the top of the elevator in the satellite terminal and at the bottom. You get your boarding pass checked and then get in line waiting for the bus. The top had a ton of people in line and I overheard a Delta employee asking people what time their flight was. The bottom had only like 4 people waiting.

So perhaps consider going to the bottom via the elevator or escalator if the line at the top is too long, or vice versa.

Sounds like you should budget about 30 min for the transfer.

Good luck.