I'm not sure it is a valid scenario. For me if you need to update the value of the asset for after the first line, you need first to post this line.

For example:
- Today is 14/12/2020.
- Create an asset with value 1.000€ and start date 14/12/2020 and end date 31/11/2021, and have defined a monthly frequency
- Click "create lines", it creates 12 lines with the first date 31/12/2020.
- Click "run".
If before you click the wizard to create the move for assets need to update the amount of the asset, for any reason, how its not possible to draft the asset, need to use the "update" wizard. If you click it:
- Fill the new amount to 1.200€ and in the next step, how the date will not be in the domain you could not finish the update.
latest move date: will be 30/12/2020, because any move are created yet.
next depreciation date: will be 31/12/2020.
And the domain say that the date will be great and less, but not equal.

If you create an asset and create it's lines, and after run it. If you have any move create yet and need to edit the asset, as is not possible to draft it, If you try the edition throw the update wizard, you can't do it because the "date" domain.