Don't forget that the 109 have a nose down attitude flying straight and level ! The only way that you can be sure you fly level is by closely watching your altimeter. Then you can reach the max speed. If 500kph is hard to reach deck without a very shallow descent, 490ish is relatively easy.

Sry for nursing you that way but it's not specifically after you. I am just fed-up to read that claims here and there again and again...

~S!