Email Signatures - Send As, and Send On Behalf - Which Sig is applied?

Example 1: User A has the Send As permission to the User B's mailbox. When User A sends an email and enters User B's email address in the From field, the message will be considered as sent by User B. Therefore, the rules covering User B will be executed (the email will get User B's signature) and the SIU service will update the message in the Sent Items folder of User B.

Example 2: User A has the Send On Behalf Of right on User B's mailbox. When User A sends an email and types the email address of User B in the From field, the message will be considered as coming from User A, and the rules covering User A will be executed (the email will get User A's signature). The SIU service will update the Sent Items folder of User A.

Example 3: User A has the Send As / Send On Behalf permission to the User B's mailbox. When User A creates an email, a signature is added directly in Outlook by CodeTwo Email Signatures 365. The message is considered as coming from User A’s Outlook email client, therefore Outlook (client-side) rules applicable to this User will be used. The user should select a signature appropriate to the message being sent from among the available ones.