Explanation for wrong charging wattage / slow charging?
85 W = maximum power used by your charger on the power supply side on AC.

49 W = actual power received by your MacBook internal power managment on DC.

Where is evaporating the missing 36 W?


Within AC -> DC transformation.
Joule effect within all conductors. This explains why your charger is heating (and incidentaly heating the atmosphere of our hosting Earth). This consumption is high because it is depending on the square of I (RI²) and on low voltage I is high.
A part is diverted by the PMC to power different parts of the computer based on its energy saving state.