When picking a logistics provider, the choice of supplier is immense. If you put your requirements in the right places you will be surrounded with offers from every quarter. The problem is, most of the offers are tailored to make sense to the supplier and not neccesarily to the buyer. For instance, a retail logistics provider may tweak their services arond the postal network in which case weight breaks will be in grams and not usually be in multiples of 10. A wholesale courier may offer a flat rate up to 1 kg, and then in 5 or 10kg jumps thereafter.
If you’re dealing with the USA with UPS or Fedex, you may be offered weight breaks in grams but that match the lb/oz equivalent (1oz = roughly 28g) and so on. There are also almost always hidden charges, like fual surcharges, dangerous goods (Perfumes) charges, oversize surcharges, overweight charges. Some price according to a volume (Length x Breadth x Height), others strangely price according to Girth x Length.
There are many situations too where outside influences can affect how much you get charged, for instance: Imagine a box packaged nice and square 10cm x 10cm x 10cm. When it leaves your premises it volumes at 10x10x10. The conversion factor for say DHL express shipments is 5000. Rough calculation (length x width x height (cm) / 5000). This gives us a volumetric weight of 0.2kg. If we are being charged £10/kg the charge for this shipment would be £2.00 right?
If another parcel en route to DHL was to fall on top of your parcel and squash the box a little, DHL does not have time to measure each box manually, they have scanners that measure the widest point of each side. So a squashed box may end up as 10cm x 15cm x 10cm, and the cost of shipping would then be £3.00 because the package would return a volume of 0.3kg.
So, many factors affect logistics costs and services, we will help you understand them all.