Meter Reading

Hi
I have a fuel vehicle that issues fuel in litres and adds the throughput to a totalizer.

For example meter reading starts at 123456
Fuel issued is 200
Finish meter number 123656

The next record the meter will start 123656
Then any issues 100
Finish meter number 123756
As you can see the finish number becomes the start number for the next record. There may be 20-30 issues per day. The fuel amount will be entered by the user and I would like to always have the start figure visible prior to entering the fuel amount so that errors could be detected.
I would also like to be able to reduce the amount of fuel in the vehicle by the amount of fuel issued and then increase the fuel amount when fuel is added to the vehicle.

Any help would be greatly appreciated as I have now been trying to work this out from various methods for nearly 2 years and become frustrated.

As the database will grow, would the calculations etc if done via a query take longer and longer. I expect approx. 5000 transactions per year at the moment.

Thanks again in advance.
Coops:banghead:

Attached is a small mdb with a sample table and form.

Open the form, enter a value in the FuelDispensed the yellow box
There is code behind the form.

Good luck.

concept
previous closing entry becomes next starting entry