The question was regarding max range, so I looked at LRC.
LRC parameters are usually, by definition, not the best way to get maximum range. The LRC data invariably has a bias to slightly increase IAS by a corresponding small reduction in range. ie, you save a bit of time at the expense of a slightly higher fuel burn.
Wind velocity also clearly plays a part.
If you really do want to achieve maximum range you have to fly at an IAS that corresponds to minimising: (Fuel Flow)/GS