At no point has T-Mobile included band 41 in this data.
They also exclude band 5 (which is only in Myrtle Beach, SC), band 13 (only in Puerto Rico), bands n258/n260/n261 (5G mmWave), band 46 (uses the same wireless spectrum as Wi-Fi, T-Mobile has only deployed it in a few spots of some cities), and some bands that T-Mobile has so far only deployed for testing purposes (ex. Band 48, n77) with a larger launch coming in the future.
The data I'm pulling from does include some 2G, 3G, and roaming information, but I decided to exclude that data to avoid the graph becoming too busy and hard to read.