Success Events attribution through calculated metrics and eVar allocation configuration

Hi Guys,

I am in process of defining allocation and participation for a new report suite and i have not used attribution model in calculated segments so far. What i am trying to understand is that, if my eVar allocation is configured to last (most recent value) and if i make a calculated metric of a success event and select linear option from the attribution model.

1. If i see this eVar against my calculated success event metric in workspace, how will eVar values finally get allocated?

2. Will the calculated metric override the back end configuration

3. If it won't override, what are some other options to use the attribution model?

Thank you in Advance.