I may be too late, but I have one on my s7e dual sim. With it I can call and get calls to and from pldt land lines and other land line plus numbers from the same area code (02 for Metro Manila). Doesn't matter if I am in another area as long as there is a signal. If memory serves, calls to other PLDT area codes can be activated as an option, and the rate is Php1/minute.

Globe duo might be a better option but I don't know much about it.