I am not a professional repair man. I recently had reason to need an ignition coil for a Stihl hedge trimmer. I thought Stihl parts would be "fair-traded" so every dealer charged the same retail price. Just for shits and grins I shopped several dealers. Wow, was I wrong! Prices ranged from $30 to $50. And, I didn't shop all the dealers in range. Figured $30 was as good as it would get, maybe I was wrong??
The local dealers set their own pricing scale. It is the same here with Stihl dealers. This is why went thru several dealers before the one I now use. One was nearly twice the others on pricing. Even have to pay the same as the end users when comes to Stihl parts.
For the most part I use my distributor price files. Even then you can find one distributor charging more for some OEM parts than others. One example is the seats I brought back in June. One distributor wanted $180 ea cost with a retail of @$230 for the same seat as the other that was under $100 cost with a retail of $150. This is why I have two main distributors.
For a while I was having to bump the retail price from my distributors as they started charging 3% surcharge for paying by credit card. But I now have that resolved and my retail prices are now back to normal. Even 3% surcharge made some of parts cost more than the suggested retail prices. MTD is one of the worst to have razor thin price margins for us if we stick with the price files.
Anyone in business will tell you there is a lot cost that we have to cover at times. This why many of us have in house part inventories which help to both keep our costs down and the retail prices down. This allows us to buy in larger quantities to reduce our inbound freight costs.