My expander has a leak. Does it need to be replaced? My surgeon says no. (Photo)

Bilateral mastectomy in June 2016. Radiation on the left breast and tissue expanders at time of mastectomy. I clearly have a leak in my right tissue expander. It is about half the size of the radiated left breast, and has at least 300cc more saline fill. Surgeon says no, just keep coming for fills to keep the pocket open for six months until it's time for implants. Should my expander be replaced or is it acceptable to just put in 100cc every two weeks and leave it much smaller than the other?