It's speculation on my part, but I think that what is now being seen may be what has already played out.

There's a Government of Sint Maarten post from 1/26 on FB entitled ** Prime Minister Silveria E. Jacobs meets Préfet Délégué Serge Gouteyron to discuss synchronizing measures to safeguard public health **

One line in the post reads as follows: Prime Minister Jacobs stated, “The cooperation meeting held was a fruitful one in which much agreement was made moving forward with the established health protocols being implemented by both sides of the island in combating the COVID-19 virus. We have already synchronized our travel restrictions to both sides of the island in order to avoid importing the more contagious new variants of the virus to the island.

Synchonized travel restrictions sound like both sides have agreed on 72-hour test requirements. French-side was never going to change to 120-hours. They can't. That decision comes from much higher up the food chain. The only way that the test requirement could be synchronized is if Dutch-side backed off from 120-hours.