Speakout has been charging the 25 cent a minute rate for at least a year. The only difference is the 25% extra airtime vouchers have dried up as of late. The only company that still charges 20 cents a minute is President's Choice Mobile. I doubt Speak Out will change their rates for 2 reasons.

No one else is doing it. Other than PC Mobile, who else is there?
I suspect Rogers is using their velvet glove with an iron fist. Since Rogers owns the network, Speak Out cannot do too much to antagonize the owner of the network.