I made a comment earlier in this thread about having to order direct from MRC. The problem is if I need a $3 replacement part, a couple cans of paint for the body, and a $4 set of antanna tubes in assorted colors.
If MRC parts were at Tower, I'd place one order and pay one shipping charge.
Since MRC is not at Tower, I need to pay $3 for the part, plus MRC's shipping charge, PLUS the things I get at Tower PLUS their shipping charge.
So, for small parts, we (the consumers) pay as much (or more) for shipping as we do for the part.
If I was the head of MRC, I'd say "we need to do whatever we have to do get people to buy our products, if that means we lose some profit to Horizon or Tower, that's fine". I believe you would easily make it up in volume.
To be honest, I probably would have bought an SB V2 instead of a Dark Impact if the SB V2 had spare parts available 1) at my LHS, or 2) at Tower or Horizon.