Tab key - moving from Account No. to Amount, Service invoice

I've been using MYOB since before BusinessBasics - since Premium-something(?) back in the late 1990s. I've been using computers since I was in school in the 1980s, and in my work since before there was a mouse to hold on to. I like keyboard shortcuts.

I'm entering Service-type invoices into AccountRight. I can <Tab> from the Description field to the Account No. field, but then <Tab> takes me to the Description field on the next line down, bypassing the Amount field.

Am I missing something, a setting perhaps? Is there a flaw in my logic that <Tab> should take me from field to field across the line before it drops down to the next line? That's how it worked in BusinessBasics.

Thanks. :-)