The drawback is that it's more intended for coin properties based on difficult and similar parameters.
Sometimes it's easier to just set profitability in BTC per MH/s, and I can implement that for you over the HTTP API in the next release if needed. It could be something like:
POST /api/coins/LTC?profit=0.000014
HTTP API access for this would be great though, I would love to write an external program to gather bleeding edge coins and update them in AM.
I will add the HTTP API in the next release.
While you're at it, can you make *ALL* coin info available via the API? It would be nice to query AM for coin prices instead of writing more of my own stuff. I'm working on AM plugins at the moment and would like to use its features as much as possible.