Originally Posted by
flyer4512
Should the hotel go up in price ( points) before I book (December 2017) and I didn't have enough Marriott points could I pay the difference in cash ?
Cash+Points works if you want to add a night but not to upgrade a certificate.
So if you had a Cat 7 Certificate and the Hotel became a Cat 8, you can not pay to make your certificate a Category 8.
I guess technically you could pay by buying points to make up the difference but don't think that is what you are asking.