Billing Total from another table

Can anyone help find the errors in this code?

= Table.AddColumn(#"Changed Type", "BillingTotal", each
let
projectID = [Project_ID],
fees = if Table.SelectRows(ForecastBilling, each [ID_Project] = projectID)[Unweighted Fees] <> null then List.Max(Table.SelectRows(ForecastBilling, each [ID_Project] = projectID)[Unweighted Fees]) else 0
in
if fees > 0 then "Billing" else "Pipeline"
)