What the OP is talking about is an aggregate, ie. two distinct pieces of software talking to each other over an interface, which is explicitly "non-viral", cf. AGPL v3 § 5.
That being said, the AGPL v3 is on the more arduous side of things, so it's easier to avoid them completely in a business context.
Sure, that seems like a reasonable interpretation to me.
However, I don’t have any specific recommendation against AGPL v3. Accounting is just one specific field where licensing virality could have particularly complex implications.
That being said, the AGPL v3 is on the more arduous side of things, so it's easier to avoid them completely in a business context.