Derive correct company value based on Legal Entity

Summary:

In the current design, we have multiple legal entities in one business unit. In the Lease Accounting module, I could write an SLA rule based on legal entity and the system is deriving the right company value. When it comes to the AP invoices (sourced from Lease accounting), I have written an account rule to derive the correct BSV based on the Legal Entity on the invoice header and with a condition that this rule should apply only to the invoices with source lease accounting. But, still this rule gets applied for non lease invoices. Can someone share thoughts on