No, I do not think so. And with this comment, it's clear that you do not understand how this works. Oda did not draw the ball with the idea of conveying it as 646 tons in mind. He did not do calculations and measurements with the density and weight of gold in mind to make sure the ball was 646 tons.
The way it really works is that the way Oda drew it, and with the mathematic rules and weight of gold, it coincidentally comes to 646. Oda may not have intended for it to be 646, but that's the way it is. Oda did not draw it the way he did to make sure it was 646 tons, the way he drew it just so happens to come out to 646 tons.