I think the highest upload speeds I've seen online, for 4G, are in the ballpark of 40 and 50Mbps, something Jazz also manages to attain because that's the maximum real world upload speed you can get on 20Mhz (and 4G supports a maximum single chunk of 20Mhz - anything extra, and you need aggregation, but only the first carrier's spectrum is used).
So for example, if it's 5+20Mhz, you'll get 25Mhz for downloads but only 5Mhz for uploads.
If the phone reports as 20+5, you'll still get 25Mhz for downloads but now, 20Mhz for uploads.
Depends which band your phone latches on to as the primary band, until it either switches it around or you do some mumbo jumbo.
Also, it's not in any operator's interest to focus on upload speeds - everyone measures performance from download speeds.