That is not presently possible.
But I also wonder whether it is really necessary for a couple reasons:
Billable Time's primary purpose is to reduce the workload of documenting time spent on billable activities and invoicing it at some future date/time to the appropriate customer. You have obviously already recorded the time over the past year, and surely you must have invoiced for most of it already, so why go through the extra work? The only way to clear these already-invoiced entries will be to create a new sales invoice from the Billable Time module. Then you will have accounts receivable that really are not. So why not just enter the time that has not yet been invoiced?
- There is no reason to replicate old financial records in Manager, if that is why you are doing this. All permanent accounts, that is, assets, liabilities, and equity, can be set up with beginning balances. And you can set your start date to any point in an accounting cycle. But for convenience, it usually makes more sense to begin using Manager at the start of a new accounting period, not a whole year in. Recreating a couple weeks of data might make sense, but I question the advisability of doing an entire year.
Let me add that
Billable Time did not always exist in Manager. I adopted its use part way through an accounting year. I had previously categorized service sales as hourly or fixed rate. After
Billable Time came out, I renamed the default
Billable time - invoiced account as
Service sales - billable time. I left the old
Service sales - fixed rate in place, but stopped using the hourly account. I then called up the transactions that had used the
Service sales - hourly account by drilling down on its balance in the Summary. I edited just those transactions to change
Service sales - hourly to
Service sales - billable time. Now everything was in place for a complete picture of billable time invoicing, but I didn’t have to re-enter any of the actual time transactions, only edit them.