My status changed to PP about a week in as a Platinum in my MR account. I went into 8/18 with 51 nights. I have 14 SPG. The dollar amount towards Ambassador doesn't show (at least for me) until you reach PP. It is a metric to follow onto PP+A. I have not combined my accounts. In MR with 51 nights it shows my spend @ $3660. I don't remember any $75 stays at major world city & airport Marriotts. But do remember $1600 for 2 rooms for 3 nights in LAS.
On the SPG side, I am still platinum and no dollar amount shown. I think the $3660 is probably close to my 14 nights in SPG properties. I was at SEA Marriott SeaTac last night and I am at a Sheraton tonight booked via MR app in DFW because my Quantas F award DFW-SYD was cancelled due to mechanical issues. This is stay 2 of 16 in the next 4 weeks.
I do like the 48 hour check in though. I was already checked in to the Marriott in Sydney for two nights. I was able to chat directly with the property via the app. They graciously reduced my stay by one night without penalty within 24 hours of arrival.
James