Hi,  I'm not sure what you mean by poor accuracy... can you give an example?  We measure the accuracy of our forecasts in several different ways, so I might be able to comment on it if you can give me insight into which event you were looking at.  For example, I consider our forecasts of the recent 2015-16 El Nino and subsequent 2016-17 La Nina to be pretty good in the sense that we knew the wintertime state of ENSO ~6 months in advance.  For the most recent 2017-18 La Nina we issued a La Nina watch (possibly arrival of La Nina) in September 2017 and then declared its onset in November 2017.