There doesn't seem to be one post-Rosat seeing as Beerus praised the explosive power of Blue when Vegeta attacked him right after transforming. This also doesn't seem to be after Blue drained him either, since when Beerus whacked him with his tail straight afterward and knocked him into a lake, Vegeta was able to access the full power of CSSJB. Pre-Rosat though... it seems like just maintaining Blue makes you weaker even if you receive a Senzu. Which is retarded since Vegeta showed no signs of fatigue from beating up SSJ Black in SSJB, and Black still not "having surpassed SSJG" should mean that Black should be significantly below a Senzu'd Vegeta, but that's Faggotaro for you.