You may notice that when items get Checked Out / Delivered / Called Off / Checked In, the times on the Order update and can affect the billing totals (e.g. charging for an extra 4-hour block).

In order to prevent the Billing Time from updating during an Order check point, simply uncheck the box "Update Billing Time" under the Date & Time section of the page.

This will ensure that the original Order's billing times (and thus total charges) remain constant.

See below for a visual representation of this page.