I can't see why not.
I don't happen to use e-junkie for this, but I do sell blocks of time. A concept that has worked very well for me is to have a yearly retainer that is a up front fee. That gives my customers an automatic discount on hourly time.
The net effect is to give bigger discounts the more time they buy. I have it explained more fully in my e-book, but basically the idea is this:
(substitute any numbers you like for retainers and hourly rate)
If they don't pay the retainer, they pay $150.00 an hour.
The retainer is $560.00 per year. If they pay that, they can then buy any amount of hours at $85.00 an hour.
Let's say they only buy 10 hours. Those hours cost them $1410 ($850 + $560) or $141.00 an hour. A little discount because they haven't bought much.
If they bought 100 hours, their cost is $9,060 ($8500 + $560) or $90.60 per hour.
So your friend might do a retainer of $200.00 and $8.00 an hour, or whatever combination works out for him. It might not even be yearly for his case - a "forever" discount. Or it can be a smaller monthly retainer.
The idea is that the discounting is automatic - no complications. The more they have bought, the cheaper it gets for them.