Anyone able to make comment on difference for fuel economy between the BA MKII Ghia 4sp and the BF with the ZF 6 sp auto?

I had a drive of one the other day and they feel a lot more lively under acceleration than my BA MKII. It was a fairly heavy/spirited drive though and the trip computer was reading 18 ltrs at the end of it.

My BA gets about 10.6 litres per hundred k's with a mix of freeway and suburbs. Goes down to 9.2 on a trip to Augusta and back with a bit of town running thrown in.

If the town economy figures are much better for the BF, I could be tempted into an upgrade.

The 6sp. auto uses less fuel than the 4sp. due to the convertor clutch coming on in every gear, so in theory you have less slippage in the transmission. I think the difference is around 1 litre per 100k by Fords figures. The ratios in the 6sp. make it more lively to drive. If I remember correctly first gear is 4.17 to 1, second is 2.34 to 1, and 5 & 6 are both overdrives. Also there is no 1 to 1 in the box so you are always in a reduction or overdrive ratio.