Time scale for submitting 3x files to LA for billing

Law and practice Other
1

Have been told that the cut off period for billing 3x files is 6 years not the usual 3 months. Is this correct?

2

I believed it to be 6 months

3

I cannot confirm whether 6 years is correct but its definitely longer than 6 months as I have recently had some authorised from early 2025.