Dear Oleg,
Let me add some comments:
Freezing out takes place, when the rate of particle-antiparticle annihilation becomes equal to the rate of expansion.
For quarks annihilation is due to QCD processes, while charged leptons annihilation is governed by QED.
t-quark feeezes out before hadronization. At T\sim alpha^2_c m_t ttdiquark and 3t-quark states can form due to chromoCoulomb binding. The frozen out abundance of 3T states, charged leptons and their antiparticles is not influenced by hadronization, while for lighter quarks and singlet and tt hadrons hadronic recombination is possible like (tud) +(t*u) -> proton + light hadrons
Please take into account these effects
With the best regards
M.Yu.Khlopov