Is it possible to "reset" Average Cost calculations? Context: Client hasn't been tracking landed cost for a while, but now they will be. So they have a few years worth of cost with no landed cost... but now they will be tracking landed cost. Essentially they want to restart tracking the average cost now that are tracking landed cost

Write off stock and write on with right cost. Best time when they do item receipt I hope they’ll add the landed cost.

Feels like that would destroy accounting, no? They create bills for freight costs (ex: FedEx / UPS) and expense them to some account (not an accountant but its something related to inventory costs) And they've paid these bills in NetSuite. If they just write off stock at the "base cost" and write it back on with the landed cost included, then they would be "double accounting" for the freight costs, right?

They can use same account used for freight in bills as adjustment account. Yes it will be one off which can be explained and signed off by auditors.

So, does average cost only consider the inventory on hand? ex: I buy 100 Widgets for $1000 each... then I sell all 100 them Then I buy 100 Widgets for $500 each When I look at Average cost, would I see $750 (average of $1000 purchases and $500 purchases) OR would I see $500 as I only have the ones I bought for $500 on hand?

It’s based on total units /its cost for a specific period.