I as well have washed quite a few batches of yeast and have really noticed not too much consistency in the amount of yeast. On average, I have about a centimeter of nice, white yeast at the bottom of my mason jars when finished. Sometimes I get more, sometimes less.
Not sure what could cause this, but I would imagine the length of time that you wait before transferring to the smaller containers would have an affect. For example, I normally put 1 gallon of boiled, sanitized water into the primary and swirl that around to get everything off the bottom. I then take that and funnel it into a gallon jug. Throw it in the fridge for 10-15 minutes and all the heavy trub will fall out. Then I simply decant the liquid into my mason jars.
I would imagine that the longer you hold the washed yeast in the larger container, the more will fall out leaving you with less when decanting. I'm sure other factors exist as well, but those are my thoughts on the difference in amounts of yeast after washing.