SIMS is always a nightmare, for everything. It's only redeeming feature is that everyone in state education standardised on it, so it gets vendor support from a lot of other products/services.
But, to be honest, as an IT guy in education, I have yet to see an MIS that isn't at least 20% shite. They all are. State, independent, offline, web, cloud, they all have shiny interfaces on some parts and absolute trash on another part.
It's taken me 4 years to get a nice listing of staff CRBs out of our provider (who shall remain nameless). Literally to the point that I coded up an Excel with ODBC to pull in the data from the database, sanitise to something approaching order by automatic formulae, then print it so it comes out on a single sheet in a nice compact tabular format (as requested by ISI inspectors - the equivalent of Ofsted for private schools - when we had an inspection who said the default report was basically useless). They still can't manage it, despite being in control of all the reporting output via Crystal Reports and all kinds, and don't make headway because "Well, one of our guys used to work for ISI years ago and he says it's fine").
Four years to get a report, and I'm still no closer, despite pulling in every ranking person in the school to chase it, multiple meetings with them, literally supplying them a format and showing the database fields I manipulated to make it work, etc.