Hi,
60 calls is still ok, are you profiling and finding some issues on this particular access? if you do, make sure it's this call specifically and not what you do with the data, say you are getting a string and try to find a gameobject in the scene, that will be a problem. If you do general math or transforms manips, you'll be fine.
PlayMaker 1.8 will come with a new FsmArray type of variable and this is using ( I believe) built in array, so this will be an option to investigate if performance is the bottleneck here.
Bye,
Jean