Unable to caclulate tax on Assessed Vaule. any thoughts?

I have the following scenario.

a) Operating Unit = Norway

b) Regime code =  NO VAT ( Seeded) - Country code for this regime is Norway (NO)

c) Bill-To is set to a location in Norway.

1. Create an AP for  a supplier where site is in Norway. Put in the Line Amount, Assessed Value and Tax Classification code - VAT is calculate based on assessed value  OK
2. Create an AP for a supplier where site is in Sweden Put in the Line Amount and Tax Classification code. Leave the Assessed value as NULL- VAT is calculate based on assessed value - OK
3. Create an AP for  a supplier where site is in Sweden. Put in the Line Amount, Assessed Value and Tax Classification code -