Most of 2020 pesso was 20% lower and the MF still went up significantly that year. I do not know about your business, but you would not expect to pay as much in Mexico as in the US, don't you think? The Lagunamar MF are somehow more expensive now than many US locations. That's an accomplishment! The MF increases had been very modest before Marriott took over and the resort was always very well maintained and had a healthy reserve fund. I actually do not mind the 2023 increase but the previous 3 were totally not in line with other costs increases in the region.
I don't own at Lagunamar, but I agree, costs in Mexico should be lower. In fact, years ago, SPG tried several times to sell me Lagunamar (even wanted me to trade in my Maui for Lagunamar) and one of their arguments was how much lower the MFs were, for the same SO value. I guess they can't make that argument any more... but it worked on a lot of people, I think that property largely sold out. (I agree that it's always been well-maintained.)
Have you ever attended the annual meeting or read the minutes? I'm sure the MFs get discussed and it would be interesting to hear the explanation for the increases in the years where they went up a lot. Some of their costs are going to be more tied to U.S. costs (for example, I imagine all the furnishings, appliances, room supplies like soap, shampoo, detergent, etc... all that comes from the U.S.) But their labor costs should be MUCH lower and that should have a large impact. Just off the top of my head, I'd expect MF's at Lagunamar to be at least 25-35% less than a comparable unit in California. The difference used to be larger than that. (I seem to recall that Lagunamar MFs were about half what they were at WKORV, back in 2010 or so.)