IMO you are assuming that the Mp's sister recollection of this 4:00 pm is correct, and besides IMO the only statements that really counts is the one he might has given to the police not an hearsay statement made by a member of MP's family. Also, as you said, his lawyer has maintained he has not deviated from the timeline and the police have not refuted that assertion.
Why did you say then:
"Since Dale's own attorney has used 3:18pm as the starting point of the defense's 72 minute timeline that Dale had to kill Michelle and dispose of her body, I would say that, yes, it still stands in contradiction to Dale's original 4:00 claim."
and then:
"Dale's own attorney puts Michelle's arrival time at 3:18pm, NOT 4:00 pm and that is a FACT and is not in dispute".?
No it is not a fact the Dale made a claim he saw MP at 4:00 pm it is an hearsay statement made by MP's sister.
And therefore no, it is not a fact that DS's attorney contradicts Dale's statement, actually he maintains the opposite and that assertion has not been refuted by the police.
And what if is true that DS changed his recollection of when MP arrived at the condo, in what context would this be relevant?