Did not saw an another topic on the same question;
When becoming a Secutor, does the player still have access to the Tech-priest career advance ?

And so, does he have to pay extra xp for an tech-priest Advance (like Elite Advance) ?

On 10/17/2020 at 1:32 PM, Elar said:

When becoming a Secutor, does the player still have access to the Tech-priest career advance

Yes, you miss only one rank from tech-priest career - the one that was replaced with Secutor alternate rank - and only for this missed rank Elite Advances are needed.

Inquisitor's Handbook, p.52-53.

"Example
Junt Yeager, a Guardsman character takes the Alternate Rank Malfian Bloodsworn, exchanging his usual Rank 5: Veteran for Rank 5: Bloodsworn, and fulfils the requirements listed. He doesn’t cease to be a Guardsman; he is just now a Guardsman who sidelines as a murderous bounty hunter. Junt’s player now has access to the Skills and Talents listed under the Bloodsworn Advances at the costs listed there, and may spend xp freely on them
from this point forward. However, all this time gallivanting around bringing down recidivists for money means he misses out on certain opportunities from Guardsmen Rank 5: Veteran. When he moves onto Guardsman Rank: 6, if he wishes to still obtain these (and has the xp to spend), he must pay for them as Elite Advances."

in our group that elite advance is +50 points, until rank 9.

After rank 9, all main career option paths are available at base cost, but not any unselected alternative ranks