The seed-to-sale software in dispensaries tracks every gram of product sold in an effort to reduce 'diversion' to yutes under 21 and to get every spec of taxes. You will be in the database.
To compare dispensary-grown medical grade product and street weed is comparing apples and oranges.
Street weed is usually treated with fungicides, pesticides and heavy metal infused fertilizers or insecticides to maximize yield. It will also have mycotoxins and mold from the growth, fruiting and drying/curing process, and insect parts in the flower, spider mites, aphids, thrips, etc.
Dispensary products are lab analyzed before sale and those poisons must be in parts per billion to pass. Meaning the growers aren't using them for fear of losing a whole batch from sale sanctioned by the state.
Street weed doesn't have to meet parts per dozen to pass.
Personal growers can control their fertilizer and pesticide regimens, but any large scale street weed grower simply isn't. Period