Although the partial DIN 1715 spec I attached earlier is of poor visual quality, I really should have read it with a little more attention!
At the bottom, we can clearly see the metal composition between A and B is different (Kanthal specs also show this as 0.5Cu is added), however the specific deflection is identical at 15.5 for both. Also, compare this with both TB1577A/B products from Kanthal (155TB1577 and 155CTB1577), these have the a specific deflection of 15.6 each.
More to the point, my VFC has no A marking, G.RAU have confirmed that this indicates it's a B part and so we now know that A=B=15.5 specific deflection
or TB1577A-GE = TB1577-GE.
So, one could conclude that although the alloy composition is different between A and B, the deflection is identical and therefore although my car has a different bms to others it's CoE is the SAME, contrary to what others have previously hypothesised!!
Therefore, when Mercedes changed from 119 200 00 22 to 119 200 01 22 on the 500E/E500 they did NOT change the bms because this wasn't required, they changed the airflow/temperature characteristics surrounding the VFC - or/and perhaps the internal characteristics of the VFC. Also, a few posts previous shows how the viscosity of the silicone fluid within the clutch can significantly change with temperature - bringing me back to my original thoughts of VFC fin and cowl design.
The VFC's locking point is NOT solely dependant on the bms, there are many factors significantly influencing this.
If I could get a reply from Sachs I would love to hear what the changes are between our VFCs and the 'Tropical' versions - because my bet would be no change in the bms..however they refuse to answer by email
Lea