Something thats kind of related to this point is say I have 10 new items ready to add to my shop. Instead of adding all 10 at once I'll add 1 a day over 10 days. I've found loading your shop all at once seems to water down the results. New listings get a bit of a boost but I believe the algorithm looks at your shop as a whole and it won't give you more of a boost when you add more listings.