That schedule is the most fucked up I've ever seen created. So you have a major football stadium that will often have games that kick off at 8pm Monday to Friday, so you decide to start running a direct tram there AFTER that time. Similarly at weekend. "Hey a stadium holding 54,000 people often play every other Saturday between 12.30 and 5.30pm. Tell you what, we'll run a tram directly there starting at 6.30 pm " Genius. We may get lucky on a Sunday though on the odd game we play then.
Anybody who thought this scheduling up is either on drugs, a rag or hates the passengers that help pay their wages. Probably all three.
It's really not that complicated.
Before 8pm, trams run every 6 mins from Etihad to town - half then go to Media City, half go to Eccles.
After 8pm and on Sundays, trams run every 6 mins from Etihad to town - half then go to Altrincham, half go to Eccles (think frequency is lower on Sundays)
So you (like me) might think it annoying that I can't always get a direct tram to the stadium. They'll be other people who live/work near Media City who might wonder the same but the other way round...