By way of experiment, I put "Nicola" in A1 and filled A2 onwards with
"Pete", and then tried various cells down column A to see how they
would autocomplete.
Cells A2:A51 autocompleted "Nicola" after entering "N"
A52:A111 autocompleted "Nicola" after entering "Ni"
A112:A140 autocompleted "Nicola" after entering "Nic"
A141:A160 autocompleted "Nicola" after entering "Nico"
A161:A212 autocompleted "Nicola" after entering "Nicol"
Beyond A213 there was no match.
Obviously, a slightly more complex algorithm than I had originally
concluded some time ago, but I was also surprised at the limited range.
Hope this helps.
Pete