section 104 of the RMA Guidelines for Loss Adjustment:

C Acceptable Scale Types
Acceptable scale types are, as follows:
(1) Non-portable farm scales,
(2) Commercial elevator scales, or
(3) Grain carts, provided the grain cart:
(a) Can produce printed tickets showing the weight, or
(b) Has an integrated display panel to show the weight of the production in the cart, provided the cart is available so the capacity of the cart can be determined.

If you keep reading, combine monitor records, load records, or structure markings are also acceptable for seperating production between fields. 

I would really like to know where this misinformation keeps coming from.  All the lies I heard about production record requirements kept us from using crop insurance for quite a few years, until someone finally showed me the actual rules.