If you haven't yet noticed, Marriott has added a Money Spend tracker on our Account Activity screen on the App. It is directly under the number of Nights. Mine is shown in USD. For me, this total reflects ALL my marriott spend, including taxes. So, I assume the total $ amount is the total $ amount from the statements issued by my hotels, or it is the $ amount recorded by Chase as a Marriott spend amount that was used to determine 6x the points transferred to my MR account. Either way, I'm glad it includes ALL $s spend at Marriott.
For my UK Brothers, do you see it in your app is pounds (GBP) brightlybob vs. USD?
CORRECTION: Update to above: The Spending Tracker is ONLY reporting the Base Room Rate from my actual Hotel Bill, nothing else. This also seems to match the T&Cs where it talks about excluding things like Taxes, Parking, Resort Fees, etc. My bill did not include any food purchases, so I'm not sure whether those would have been included or excluded from the Marriott Spend tracking. Sorry if the original content mislead anyone. My apologies.
I've also heard from UK folks that the Spend is reporting only USD, so not sure whether that will change or how Marriott is converting Sterling to Dollar.