My 7 week old is still nursing over 40 minutes!

My son just turned 7 weeks yesterday and he is still nursing anywhere from 40-60 plus minutes at each feeding. He is also still needing to feed at the 2 hour mark from the last start, unless I can get him to nap. In the evenings he is sleeping 3-5 hours at a time but is up for a good hour to nurse. I track his feeds on this app and other moms average only 18 minutes! He is tongue tied but the doctor doesn’t seem to think it’s an issue. Opinions please!