Let me help in crunching down some simple number to help understand this.

Assuming that an app owner wager 100 bitcoin of volume in his 1 % house edge site, that gives him half of the house edge back to him as app owner

So 50 % of 1 % house edge * 100 bitcoins = 0.5 bitcoin

Assuming that there is no variance or anything at all, he will lose 1 bitcoin for every 100 bitcoins volume

Which means he lose approx 0.5 bitcoin every 100 bitcoin volume

In the end it will be the same as normal player betting on a 0.5 % house edge?

P.S : Is the share of app profit still 50 % of the house edge?