hm , same things i made, with my own code , and simplified
direct count up to 400 sec (32 bit)
and ocxo control over 12bit dac , vref - lt1021, and sum. ampl that summing from multiturn resistor and dac.
using multiturn -do adjust coarse, when dac set in the middle; then dac\code do fine adjustment.
no learning , just count difference and proportional steps in adjustment, as dac change fraction of output, it about 0.5mV step. seems sufficient.
stunning prototype
napkins left - ocsx and voltage thingi
foil right - ublox clone
3 colour led - switching in blue in a few hours, means calculated and expected counts for 400 sec timeframe match , seems sufficient for me.