Can't say for much in Toronto, but here in BC I see it all the time. Paramedics out here get paid "$X/hr" (possibly about 12 or 15/hr) when on standby, then it jumps to around $30 or $30/hr when they receive a call. They continue to get paid with this "Call rate" until the patient has been brought to hospital, triaged, and the Paramedics radio in that they're cleared from that call.
You should see the number of paramedics out here that take their sweet arse time to do anything, just so they can get paid more. Also, they stand around in the triage area or the ambulance holding area for up to hours even, doing nothing, their patient was transferred into hospital care and they're good to go back out... but they stand there and draw as much money as they can out of the system. I'm not painting them all with the same brush, there are many good, honest and hard-working paramedics... but some... are not.
Ever wonder why it takes so long for an ambulance to show up? Here's part of the answer.