I was thinking the same thing about the voice vibration in this week's episode. Why was he bothering to disguise since they know it's him?
Of course the answer may be that when he powers up as the RF, maybe he is physically changed from his Harrison Wells disguise. Or, he could have been doing it for so long that it's an automatic reflex by now, it would actually take more conscious thought and effort to NOT do it.
I figured that when he went back in time, he didn't realize that killing Barry or in effect undoing his origin, he'd lose his powers and be unable to return home (or why he'd assume he had a home to return to, might now be a future all ruled by Grodd's descendents). Maybe they'll explain it in the next issue, but if they do succeed in undoing RF's time trip, then how does Barry and the others still get their powers since there won't be an accelerator accident? I think they tied way too much to the accident and Wells/Thawne's machinations in this alternate timeline to properly address and we know that many of the characters will still be running around afterwards.
I figured they just kept the RF vibrating thing because it's easier to hide the stunt double. I think the actor that plays Wells is in his early 50s, and while he seems to be in good shape for his age, and isn't exactly a spring chicken.