I also purchased CSA insurance for an upcoming cruise and if you wanted to pay a premium coverage, it would cover pre-existing conditions. Although it did come with a higher price, but if you should need it, it was available.
I've also used this insurance before with no problem, but also haven't had to make a claim, although have heard of people that did and got prompt payments when they provided the proper paperwork. Good luck and happy cruising.
Tuesday Chat HOst