[Postman]

My thoughts are that it is a brilliant example of a terribly written specification.

I said I'd seen something like this before. I looked through my folder of specifications and found the document I was remembering. This is from a show mixed December 2009. These specs are no longer in use, they were revised last year to ITU BS.1770, but I thought it would make for interesting discussion:

3.1.1 The operating level for reference tone and legacy analog system calibration is -20dbfs per SMPTE RP155.

3.1.2 Programs are to have average loudness levels that fall between -28dbfs and -20dbfs during the majority of a program as measured on a digital meter calibrated to the RMS/VU ballistic. Average loudness should not go above -17dbfs at any point during the program.
The bolded line above means "the VU meter cannot go above +3VU", since the calibration level is -20dbfs, and 0VU=-20dbfs sinetone.

3.1.2 Programs are permitted to have audio levels that regularly peak near but not above the following limits using a digital peak meter:
SD: -10dbfs
HD: -3dbfs

3.1.4 (excerpt) Programs...must have dialog levels with a value of -24dbfs+-2db. Programs may have peak music or effects levels up to the level limits specified in 3.1.3 during moments of dramatic impact as long as dialog levels are maintained as specified.

When I read your specification I think it is a similar circumstance, where the "average loudness" is probably based on RMS meters, not instantaneous peaks. My spec was to peg average levels to -17dbfs, your specs say -10dbfs. However, you'll never know what your specs mean until they explain it.