I know there are many recent threads on this subject one of which was started by myself but the situation, not only gets confusing by the different treatment by individual Hilton hotels but also very recently the staff within a hotel.

I checked into the Hilton London Kensington last week at 7pm, Ok the lady said politely and friendly we have upgraded you to a "suite." Also here is a breakfast voucher for the restaurant.
I smelled a rat immediately, the Exec lounge would have been able to give me continental breakfast anyway. I decided to bluff it out replying that after a long day and an early flight I could't wait to have a quick drink before a shower and was making my way to the Exec lounge!
Shock, a look of horror appeared on her face and after 5yrs as a diamond member without ever having been refused access, I realised my time had come to join the rest of the people on this forum who have been refused entry.
She stated awkwardly that due to the fact that I didn't have an executive room I wouldn't be allowed access and that things have changed within Hilton to Exec Access recently! Ok I said, so upgrade me from a suite to an exec room - err there was none left! After much debate and a queue a mile long behind me they finally acceded and agreed access, "as a one off.", (when I saw the exec room I had a quick drink and left - one of the smallest, dreariest rooms in Europe with scant snacks), I should have saved my negotiating skills for a lounge somewhere like at Tel Aviv or Park Lane, London.
The next morning on checking out, a different receptionist informed me that he would have had no compulsion in offering a diamond member access to the exec lounge, irrespective of the room offered. So where is the consistency - maybe it's pot luck not just on the hotel but on the receptionist you come across, She seemed in a good mood so I am at a loss as to her attitude. The purists among you would say, you got your upgrade to a suite,(two tiny rooms adjoining which would have fitted into a dolls house) and your breakfast voucher - deal done and correct!
Well here's another thought though, when I got to my room that night I decided to test them and phoned central reservations, remember this is after 7pm, asking if there was any exec rooms at the Hilton Kensington for myself and two colleagues, that's 3 rooms required - yes sir, they're available was the reply.
So why was a Diamond member who gives Hilton 50+ nights a year lied to and refused an Exec upgrade when rooms were available and at that time of night had very little chance of being sold, I'll tell you why - down right indifference by certain staff to the Hhonours programme these day's

As the London song goes, "Fings aint wot they used to be."