Subsistence/Dispensations

HMRC Guidance (EIM05200) says: -

"The employer should have procedures in place to ensure that:

Scale rate payments are only paid when the employee has incurred an allowable expense. A scale rate payment which is paid irrespective of whether the employee has incurred an allowable expense is simply a payment of earnings within Section 62 ITEPA 2003 (see EIM05100)."

The purpose of scale rate payments being that the receipts do not need to be kept, how then can the employer be sure that the employee has incurred an allowable expenses if there is no receipt.

If I use HMRC benchmark rates as an example, is it enough to keep a record (timesheet?) that the employee has been at a temporary work place for a period of 5 hours or more and therefore can automaticlly receive £5 (one meal rate) tax free regardless of whether or not a meal has been bought?