Facebook policy is very odd in this subject (almost dictatorial). They use to change it, with no previous warning, or disable permissions. You never know if it was due high demand (a hard limit), content, abuse, or errors.
Our advice is to have *Your Own Facebook App*, avoid duplicated posts or errors, and be ready to renew it every once in a while.
We would like to have +a paid service from Facebook+. Now, they just offer a (free) service according their business objective, with no professional support (no associated costs or guarantees).