I Tongue-Block and bend all the time when I use my Tongue-Switching technique. But, whenever possible, I use the Whistle Method for bending and go back and forth between the two single note methods to accomplish the sounds I want. I think Jerry Portnoy also does and recommends this.

I don't see any big advantages for the average person to be able to bend while Tongue-Blocking. More practice will allow you to do so, but I don't think there is much point to it. I'd spend my time elsewhere.

Play on,
Dave Gage