Until I looked at the Interval International site after reading you post, I did not know of the PTV code for The Cove. All I can give you is my best guess.
The Cove is an Island One resort and part of their Club Navigo. I am a member of their Club Navigo and know that there is a difference between the two buildings. The North Tower is the older one and supposedly has been renovated in the last two-three years (after the new building was completed). The South (newer) Tower is about 5-6 years old. They charge more even to club members (in the form of points per night) for units in the South Tower. The check-in for both towers is in the North Tower. To access the South Tower, you need to use your key card on the front and/or rear doors. The indoor pool is in the South Tower. I am not sure that if you stay in the North Tower that you can use your key card gain access to the South Tower.
I also know that the PCO and PV1 codes were used before the South Tower was built. The resort existed prior to Island One taking it over and always thought that the PCO was the code used for the owners under the previous ownership and the PC1 was the code used for owners who purchased under Island One. Some of the owners in the North Tower would have purchased their contracts before Island One started Club Navigo. Club Navigo started sometime in the early 2000's.
My guess would be that the PTV code is being used for the Club Navigo owners in the South Tower.