OK. So based on my math I'm missing 2 seeds: (I have 1 so far from the castle and all but 13 of the Wasteland's - I'm procrastinating on the one's that will be easier to do once the sandstorm being caused by Vah Naboris settles down). The load screen is saying I've got 816 seeds. 900-816-24-13=2.
I was originally missing 3. I've reviewed videos detailing the locations of all the seeds by region. I did manage to find one overlooked seed in the Central region but that was it. I was meticulous about ensuring the seed was a match by making sure the at least three markings on the map matched precisely.
The only other possibilities that could be causing issue with my math would be if the number of seeds found in the Wasteland and the Castle aren't what I'm being told. According to my sources: Castle=25; Wasteland=68.
Now obviously I've already maxed out my inventory. So should I actually give a s*** on this playthrough about getting it perfect?