The amount ALLOCATED is the 415 amount. The participant doesn't have it until then, so the $105k is what counts for 415 purpose.
We (a large, well known recordkeeper) STRONGLY discourage this for that reason, and about 60 others, including 1) the plan probably doesn't contain a provision for it; 2) the IRS wouldn't qualify a plan that contains such a provision (according to them, there are limited uses for "unallocated suspense accounts" and the client's budget isn't one of them; and 3) what happens if you have allocation conditions not met....
BTW, this has become a big issue right now, as employers are trying to shelter PPP money to qualify for loan forgiveness. No opinion on if that works or it's "fraud," but not our call.