Read the SINP disclaimers. If your application is taking longer than expected, then it's usually the case that there are integrity concerns about the application and additional verification needs to be conducted.
*These processing times do not include the average time spent waiting for additional information or time spent under program integrity review. The average processing times, including time waiting for additional information or documents from applicants, is 4 weeks longer than the times posted above.
SINP have been accurate with processing times for pretty much everyone I know who has been through it in SK.