The CTO Sweep looks at the client and office balances, but the onus is on the cashier to check the position of the ledgers before making transfers.
You would be able to allocate against unbilled Disbs which have no VAT.
For Vatable Disbs, to be able to allocate these at the point of the sweep, they would need to be billed.
You can also tick Include DUB to add the balance of Disbursements that are Unpaid and Billed, please be mindful to pay these disbursements out as they will still be due.
If you post the sweep and can't allocate at that point, this can be done at any point afterward via:
From the DPS Home Screen, select General Postings.
Select Allocations.
You can run a nominal transaction report to check if your sweep was posted or not via:
From the DPS Home Screen, select Reports.
Select DPS Reports.
Select Nominal tab.
Select Nominal Movement report (Bank Day Book).
There is also another useful report to look at unallocated credits. you can find this via:
From the DPS Home Screen, select Reports.
Select DPS Reports.
Select Clients tab.
Select Unallocations (Firm Credits).