Bolt action campaign WWII.2

[Stuart]

Historically as the war progressed, and units spent more time in the front line, the fighting strength of units diminished, and replacements were either hard to find, or without the experience.
So to recreate this, after your battle you need to roll a D6 per unit, that was removed or has suffered 50% or more casualties.
1 No replacements
2-3 Full replacements, but squad now drops one level of experience
4-5 Full replacements, squad stays at same level
6 full replacements, squad experience gains one level

Just an idea, but on a 2-3 would it just be the replacements that enter at a lower level of experience, as the surviving troops would have emerged from the encounter with more experience? Or does the drop in level for the whole squad perhaps reflect the loss of key/inspirational personnel, diminishing their overall effectiveness?