Applying too much Proofide to the underside of the saddle will cause over-softening. Before Brooks was taken over by Selle this was never given as advice. Back then it was small quantities applied only to the top surface, which of course has been "pressure rolled" and the Proofide could not penetrate this and at best could only provide a temporary waterproofing effect.

The advice about applying Proofide to the bottom came about because Selle realised that mudguards (Fenders) were not popular with American cyclists and so wanted to make the underside less vulnerable to wet and spray. The USA was targeted as their largest market and Brooks saddles sold as a retro niche product with a huge hike in price.