Questions about Phoenix Wallet (a non-custodial Bitcoin Lightning wallet)

I have some questions regarding how Phoenix Wallet behaves on its initial deposit and how fees are applied in that context.

From what I understand, when a brand new Phoenix Wallet receives its first deposit — whether via on-chain Bitcoin or via Lightning — the wallet ends up creating a very similar initial channel in both cases, with comparable capacity and inbound/outbound liquidity after setup.

If that understanding is correct, I would like to better understand two related points:

First, what is the structural difference in how Phoenix handles the initial deposit depending on whether it comes from on-chain or from Lightning? In both cases, the result appears to be a newly created Lightning channel with very similar final balances and capacity. What exactly determines this similar outcome, and what is happening under the hood that leads both deposit methods to converge to such similar channel states at initialization?

Second, why does the fee structure differ between the two methods? The first Lightning deposit incurs a 1% fee in addition to on-chain mining fees, whereas the first on-chain deposit only incurs mining fees, and yet in both scenarios, it seems that ACINQ provides inbound liquidity, locks capital into channels, and uses the same underlying infrastructure to create a functional Lightning channel. If the 1% fee is meant to compensate for liquidity provision, infrastructure, and capital being locked in the channel, I am wondering why a similar fee is not applied to the first on-chain deposit, where essentially the same channel creation process appears to take place.

In other words, what is the exact technical or economic difference between these two initial deposit flows that results in both producing similar channel states, but only one of them being subject to the additional 1% fee?