Keeping an order together

Routing works line by line, so different lines on one order can end up at different sites. That is correct as far as each line goes, and often wrong for the order as a whole.

The problem with per-line routing

An order for three items. Line one routes to Manchester because it is nearest. Line two routes to Leeds, which is the only site holding it. Line three routes back to Manchester.

Two sites, two fulfilment groups, two parcels, two lots of picking and two lots of postage — when Leeds might have been able to send all three.

What single-source preference does

After the per-line results are in, one more pass runs. If any single site could fulfil every line on the order, the whole order is preferred to that site, even where per-line evaluation would have split it.

In the example, Leeds sends all three. One group, one parcel, one lot of postage.

It is on by default.

When it does not apply

When no single site can fulfil everything. If one line is only held in Manchester and another only in Leeds, the order genuinely has to split, and it does.

The preference consolidates where consolidation is possible. It never holds an order back waiting for one site to be able to take it all.

Why you might turn it off

Rarely, but the case exists: if your per-line rules encode something the preference overrides — a site that must handle a particular kind of line — then consolidating can send work somewhere you did not want it. Turning the preference off restores strict per-line routing.

Most organisations leave it on. Fewer parcels is almost always the better outcome, for cost and for the customer.

Not the same as merging two orders

This is about the lines of one order. Combining two orders into one parcel is a consignment, a separate mechanism with its own conditions — see fulfilment groups.