Should there be a recommended upper limit for the acute flaccid paralysis (AFP) rate?

While there is a widely accepted minimum Non polio Acute Flaccid Paralysis (AFP) rate of 1-2/100,000 children under the age of 15 years for AFP surveillance, there is no maximum limit for it. This minimum rate is a requirement for Polio free certification. All guidelines and literature only mention a minimum. A co-author served with the World Health Organisation (WHO) as an AFP Surveillance Medical Officer (SMO) in Bihar, in the northern district of Supaul, for 2 years, from May 2011 to July 2013. Supaul is one of 38 districts in Bihar state of India. In this period, the AFP rate for Bihar was 40.63 in 2011, 37.38 in 2012, 29.43 till week 31 of 2013, 33.64 in 2014, 27.96 in 2015 and 24.07 till week 42 of 2016. Two questions worth looking at are: Could there be a greater focus on the quality of case investigation? Would it serve any purpose to have an upper limit for the AFP rate, so as to disincentives including very obviously non AFP cases as AFP cases?.