as you can easily see in the upper left corner, this data (and the 190A8 data too that can be found in the net) comes straight out of the department of flight mechanics. It is calculated data. And for INA-conditions (standard alitutde + temperature)
Of course every calculation uses data from flight tests or wind tunnel tests (drag assumptions), so you could say it is based on flight test data.
There exists also a engine performance chart of the BMW801 somewhere in the net. If you compare the serial numbers (9-801-5401) you can see that they´re identical.
You may ask why the A5 is faster than a A8:
-Installation of MG131 for the A8 resulted in larger bulges, more drag
-Installation of larger MG151 cannons in the outer wing section
-later a slightly modified oil cooler was introduced what caused a bit more drag, but offered better protection
-from the A6 on, for simplifiying the production (safe time, costs) the polishing process of the surface was cancelled
The data is without a bombrack (ETC 501). A better scan can be found here:
http://people.freenet.de/nik_mc/fw190_A5.gif niklas