I thought ADF dip doesn't vary with relative bearing to the beacon. The 'dip' is dictated by the aircraft charateristics and is generally 8-10 degrees when the wings are not level regaredless of RB.
I think what you refer to is that when you are 60 deg to go in the inbound turn you are approx 10 dgrees off the inbound track. Coincidentally this is cancelled out by the dip so it looks like you are showing the QDM to the beacon.
eg. Assume inbound track in 090 on a lh hold, at the gate you will be on the 120 qdm (heading 270) . At 60 degrees to go (heading 150) you have done 2/3 of the turn and have about 10 degreees to go. The qdm will be 100 but dip will be 10 degrees left reading a qdm of 090. If you rolled out at 150 the needle would read 100 (the qdm) .
(Having said that having just fiddled with RANT dip appears to be +-10 degrees heading to or from the beacon decreasing to nil abeam the beacon - never knew that)