Buying Coins At Close To Greysheet Price.

I'm at the point in my Morgan dollar collecting that the coins I want in mint state are getting pricey for me so I need to be give more thought and planning to my purchases. One of the dates I want is a 1921-D Blaze White, good or strong strike, (no toning) in MS-66. So I did some research, watched videos, etc and came up with the attached spreadsheet.

December 2024 Greysheet, which to me is wholesale or dealer-to-dealer for graded coins, is $720. The CPG Collectors Price Guidance (retail) is $1020. From what I gather from several videos is that dealers often buy coins at 20% less than Greysheet so that would be $576.

I checked out PCGS auction prices and Great Collection auction archives and looked at the history for the past two years. According to one chart I seen, the market for this coin has been level for the past three years. These two sources had sale prices from Stack Bowers, Heritage Auctions, Great Collections, and ebay for NGC and PCGS graded coins.

Oddly none had ANACS coins which reinforces the impression I have that NGC and PCGS is the standard for coin dealers and ANACS is nearly solely for the collector. I did look at DLRC (David Lawrence Rare Coins), which has many ANACS coins in their auctions, but they had none of the 1921-D in MS-66.

The SB and HA auction prices include a 20% buyers premium, GC is10%, and ebay is about 10% for sellers with an ebay storefront. So that got me thinking that if I deducted the buyers premium or sales fee from the sale price that ought to be what I should be able to buy the coin for at a coin shop or at the twice monthly Sunday 40+ dealer coin show at the VFW hall or hotel conference room near me. My presumption is that the dealer expense for these local shows is very low when compared to the multi-day big shows and shouldn't affect the coin price.

I did test this theory out twice a few weeks ago when I seen a graded coin on ebay that I wanted. I did a Google search, found their brick and mortar store, gave them a call and they sold me that coin for 10% less than the ebay price.

So in my analysis I looked at 18 coins that were auctioned that had the eye appeal that I wanted in the MS-66 grade. I deleted two outliers that were high or low on the bell curve. The result was that I think I should be able to buy either the NGC or PCGS coin for about $700~$725, just about in line with Greysheet. Presuming the dealer got the coin for about $576 that would be at least a $124 gross profit or 22% margin. As I understand it a 20% margin is pretty good for a coin dealer if you can flip/sell the coin in a few months
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So what do you think? Is my logic flawed?