SVT calculation error, when using my I-Step shipment value for Alpina EGS flash

[BAM]

Hi, 

As the title suggests, I'm encountering an error when calculating the SVT, using:
Psdzdata v4.24.12 full with esys 3.30.1

I've added the relevant FA config for an Alpina, for my 2014 F13 640d:
920, 9XA
Type code set to 5D71
Zeitkriterium left untouched - 0714

I-Step details are:


If I calculate the SVT, as a complete flash, using:
Shipment 17-04-503
Target 20-07-520
I get this error 



If I change the shipment value to:
15-03-500 it calculates without error and I can see an SWFL update


I have a few questions please:
1. Do you know what is causing the initial error, using the matching shipment level to what I've read from the car? 
2. Would there be an issue proceeding with a newer shipment value, where it successfully calculated the SVT file? 
3. Is it just the SWFL that requires updating? As nothing else is showing an update under EGS. 

Many Thanks in anticipation for any help. 

Cheers 

Bradley