Is there a way to make Zen-Cart calculate the weight of each box using integer division and modulus instead of decimal division?

Here's why:
There is a product that is shipped in boxes up to 45lbs. If 100lb are ordered it would ship like [45][45][10] but zencart calculates it as [33.333][33.333][33.333]. I did a quick test on UPS's website and it made a small difference in price, actually charging more for the evenly distributed boxes.