Please refer to pp 98/99 of 2008 rulebook .... part 2, Item A, #2.
Ponies that have received their permanent measurement card, must have their HEEL measurement taken each new year. Unlike Miniatures, Shetlands w/ permanent card do NOT have to have the HEIGHT measurement verified at the start of the show season ... the ONLY new measurement required for a pony w/ a permanent card is HEEL (not height). That's a long, long, long, long-time rule and has only varied the silly year we measured every pony at every show.
Again ... ponies w/ a permanent card do NOT need a height measurement at the beginning of the season but do need a heel measurement. A pony w/ a permanent measurement card should have its heel checked every 60 days. You also will have to be measured at Congress if you go there to show.
AHR