Speedfusion cloud help

I need a little planning help with speedfusion cloud.

I’m wanting to run a speedfusion tunnel with hot failover and fec to speedfusion cloud.

my math I think is pretty straightforward with some ‘minutes’ pulled from CDRs for the data usage:
2621.7 total minutes
estimating about 93.5Kbps *2 (for each direction) for the SIP call plus FEC overhead
Ends up being about 3.5GB to do 2621.7 minutes, or ~1.6GB/1000 minutes.
This sound right?

So is speedfusion cloud charging for just the used data, ie 3.5GB?

To clear up my confusion, let’s say I enable WAN Smoothing which doubles the data usage, so is that 3.5GB because that’s what passed through the tunnel, or is it 7GB because that’s how much data hit the WAN interface(s) at peplink’s datacenter?

In other words, do I have to pay twice the price for wansmoothing on speedfusion cloud?