Ann: Quarterly Activities and Cashflow Report, page-3

i'm not blessed with the technical knowledge of all things o&g, but i did note the following from the qrtly report on xanadu ....

"All available data is currently being integrated to estimate the range of total crude-oil in the Xanadu
structure. The data indicates that in addition to the potential of the up-dip structure previously
announced, there is now evidence that “down” structure volumes are also present within the​

currently mapped Xanadu prospect"

does "down structure volumes" mean that the find may be larger than first estimated [i.e "up dip structure volumes" plus "down structure volumes"]?

the knowledgeable ones may care to enlighten me, please!

thx