What's unclear is where that rebate comes from.....
It comes from a pool of aggregated gross profit a WS makes, including commissions, monthly fees, etc. It's not useful to arbitrarily assign the source to a particular revenue.
With that said, I believe the rebate is largely financed by reciprocity fees, low-sending fees, and order-receiving fees paid by tiny filling florists.
For a $50 order, they pay...
reciprocity fee: $2.50
low-sending fee: ~$1.00 (if they receive ~20 wire-ins a month)
FTO: $1.50
total = $5.00 per order
That it doesn't come from the order value is clear to me
You are correct.