Table rate shipping by weight - miscalculated?

Hi
I have my shipping setup as a table rate, by weight. My product weights are entered in grams. Here is how my table looks:

499:8.00,999:10.00,1499:15.00,1999:20.00,2499:25.00,2999:30.00,100000:35.00

When I put a test order through the store, the product weight is 100 grams (so shoudl be $8 shipping) but it comes up as

Table Rate (3 x 36.67grams) $24.00
Best Way

any idea why it is calculating this way?? Where is it getting the 3x? I only have one product in the cart (and regardless it only would need to ship once!) and where is it getting the 26.67 grams?? Is this something to do with having it in grams??

Thanks in advance...

I should add that this is the newest version of zencart, with no mods installed.

You may want to check your settings in;
admin - configuration - shipping/packaging

Table Rate (3 x 36.67grams) $24.00

3 is pcs of boxes
36.67 is the weight of each box

24.0 should be 8.0 * 3 = 24.0

perhaps you have a wrong setting of admin configuration. Steve maybe correct.

Thanks - the maximum package weight is exactly what it was!!