I have one breast surgeon that does fantastic oncoplastic work and still manages to get a nice, well delineated, cluster of clips clinically where I would expect them to be for APBI. For low risk cases I still offer these patients APBI. I think her technique is more of a mastoxpexy though than a ton of "scrambling" of the tissue for lack of a better term.
However, some of the other breast surgeons leave me with no discernable cavity when they do their versions of oncoplastic reconstruction so I face your conundrum and practice like you as well - they typically get 40/15. Elderly patients not concerned with cosmesis that need whole breast I have integrated 26/5 into my regimen.