jer / full vowel question

The Russian ko mné, k tebé thing fascinated me for its similarity to
PIE secondary 1sg -om vs 3sg -t (vowel / no vowel), so I looked up the
CSl equivalent. And it's

A mIne,, tebe,
I mUnojo,, tobojo,
L mIne,, tebe,
(but
D mene tebe)

What a cop-out. I thought I was going to get an explanation of the
very un-Havlík variation in the designation of heavy syllables before
nasals vs stops, but no, the designers of OCS introduced a jer / full
vowel distinction between the pronouns of 1st vs 2(and 3)sg, probably
to explain this very phenomenon. Anybody who can explain what really
went on here?


Torsten