So you created a spreadsheet in order to determine the THC/cost ratio as a factor, but then you did not sort your rows based on that factor?
Multiplying by the percentage shifts the calculation to determine the price of THC, not the price of the weed overall.
Example: You have a jar with 100g of weed you bought for $900 (bulk discounts ignored). You know the weed has a THC content of 22%, which equals a factor of 0.22. Multiply the 100g in your jar by 0.22 and you get 22g of pure THC in that jar. 900/22 means around $41 per gram of THC.
That way, you can easily compare price to THC ratio, that is, you will know how much you paid for a gram of THC, not for a gram of weed.
Put that new value (cost of THC per gram) into a new column and then start sorting all of your rows by that value in ascending order. Thay way, you can instantly look at the optimal entry (the top one), but also determine similar products, for example if your source is out of the best product, or it's generally unavailable for someone without re-scanning the whole table (making it pretty useless).