Would you want all the grout replaced in your shower?

Remodeled with a completely new shower last September. Recently the grout, an expensive kind with claims as to no staining and mildew resistant, started changing colors, from white to brown, was originally Buff which is bone to tan color, and it also started coming out of the grout joints in chunks, off many floor spots. Called the contractor, he admitted problem, no problem fixing. Sub-contractor says it's only a shower floor problem where water sits and says the company making the grouts says the same. One chunk came out of the wall above the shower bench and grout 2 inches above the floor is changing color along with grout along the edge of the floor coming out heavily. Floor slant to drain is perfect. Sub-contractor does not want to remove wall grout, nor ceiling grout. Says that will be fine even though I point out the changes above the floor. Removing wall and ceiling grout will take a long time since it's not yet saturated with the problem. Sub-contractor keeps trying to talk me out of removing grout not on the floor yet he does not plan to use the same product when the grout is replaced but instead regular grout with a sealant. Bad grout is bad grout. I want all replaced, don't care that they will use the old reliable grout, and the main contractor has no problem having it all replaced. My view is the ceiling and wall grout will eventually fall apart but just may take longer. Sub-contractor just doesn't want the tedious job of removal. How would you feel about the grout in your shower if you were in my position? Just want to let the Sub know others points of view. Thanks!