Period Exchange Rates shouldnt overwrite user amended rates on CB Inter Bank Transfer

Scenario:

Period Exchange Rates are in use
User uses inter bank transfer
User posting a transfer between cashbooks with different currencies.
User adjusts the exchange rate to reflect what was paid and what was received in respective currencies.
User then sets the date of the transaction
Outcome

When the date is change period exchange rate functionality kicks in and overwrites the user amended rate.

If the user is not paying full attention they may not see the change may lead them to post incorrect values.

Behaviour observed in S200C Standard not yet tested in other versions.