It's hard to say, however it might be 4G Sucks in your specific area.
Here is why I say that:
At my house (outskirts of town) I get 2-3 bars of 4G LTE Service, HOWEVER, I only get 0.3 MBps down and 7.5 MBps upload speeds.
When I drive into town (different tower I guess) I get 20+ MBps download and 10-12MBps upload also with 2-3-4 bars of 4G LTE.
I think its the Towers tbh.