Fullfilling orders

So,

We have a lot of legacy orders when they were never fulfilled due to an issue with our API. This means that we need to tidy them up at some point.

So I found the API that we use currently for fulfilling the orders: [email removed]

This was great, however it then showed a massive jump in our fulfilment times on the homepage. I was hoping that somehow I could backpost the fulfilment dates using the created_at key, but this didn’t work.

Is there a way we can fulfil the order with our date (taken from our shipping company) or are we better just closing the orders as fulfil I’m guessing reduces the inventory?

Thanks,