He/she is likely using a secret menu in the Roku, which for years now has not been accurate at reflecting the wireless throughput nor the stream bitrate.
The “Display type” setting on the Roku is separate from the Tablo recording quality setting. I would leave this as “1080p HDTV” regardless of the recording quality setting you use on Tablo.
The 1080p recording setting on the 2.2.2 firmware records 1080i 30 fps source content as 1080p 30 fps h.264 video, which the Roku 3 has no problem playing. The 1080p recording setting on the 2.2.2 firmware records 720p 60 fps source content as 720p 60 fps h.264 video, which SOME Roku 3’s have problems playing which results in the “loading… please wait” messages.
The solution for this until Tablo Support releases the 2.2.5 firmware is to drop down to the 720p recording setting. Or you can contact Tablo directly and have them release the beta to you for the 2.2.5 firmware. The new recording quality you will want is the ‘1080p 8 Mbps’ setting which does not record in 60 fps.