That's promising, but I really wish people realized that there is much more to this issue than DL/UL speeds - especially if you are in a strongish signal area. The cellular problems with the XS happen in WEAK coverage areas. I don't really care if I get 10MB or 50MB down for the most part. The difference is negligible and does not provide a significantly different user experience for what 99% of people do on their phones (email, texting, social media, web browsing, etc.).
What I do care about is that my phone selects the best signal/band as quickly as possible and that it maintains the best connection at all times (meaning that the phone is aggressive enough in seeking out the "best available option" when it needs to).
If the signal is strong enough, a higher frequency band (i.e. band 2/4) is fine. When the signal gets below a certain threshold, it should drop to the appropriate lower frequency band (i.e. band 13) in a timely manner. All of this should be seamless to the user and the user experience should be as good as it can be given the cellular reception in a given area (a variable Apple certainly has no control over).
All of this to say, I don't give a crap what my speeds are on a speed test as long as my phone is giving me the best user experience it can. If it's not connecting to the appropriate tower or band, then Apple is holding the user experience back. If the network/carrier/capacity sucks in the area I'm in, then so be it.