Audi oil consumption standard of up to 1 quart per 1,200 miles, or 1 liter per 2000 km.
So the 1 1/2 qts is considered normal to them.
Here is their explanation:
In order to provide effective lubrication and cooling of internal engine components, all internal combustion engines consume a certain amount of engine oil. Oil consumption varies from engine to engine and may change significantly over the life of the engine. Typically engines with specified break-in periods consume more oil during the break-in period, and the oil consumption will stabilize after the break-in period. Refer to the Owners Manual for specific break-in procedures.
Under normal conditions, the rate of oil consumption depends on the quality and viscosity of the oil, the RPM at which the engine is operated, the ambient temperature and road conditions. Additional factors are the amount of oil dilution from water condensation or fuel residue and the oxidation level of the oil.