I don't know that we should assume that. The public statement - that Middleton's visit was about getting the Harpers comfortable with the Phillies ownership - might just be valid. We don't know.
What we do know is that, in taking such a public involvement, Middleton has (as others have noted here) essentially taken his front office staff (MacPhail, Klentak) off the hook if they don't succeed in this negotiation. He's taken responsibility - he's taken 'ownership' of the negotiation (regardless of who is talking to whom, and when).
But "raised their offer"? Who knows.
It's hard to just be patient and not get frustrated with the process - it's best to not get too invested in Harper - either "we need him" or "he's over-rated" or whatever. As with all roster questions, it's out of our hands.
I'm looking forward to seeing what McCutchen, Segura and Realmuto add to the club, day in and day out. If Harper is added - or if somebody else is - I'll look forward to that, too. But in the meantime... there's a ballgame to follow!