Sorry, but FINRA states that daily short volume isn't accurate.
I bet your data comes from the OTCShortReport - the site is for paid pumpers to use so they can show investors it is the shorting that is causing the PPS to bleed out.
FINRA states the only accurate short sales data is the Bi-Weekly report - why do you think OTCM uses the Bi-Weekly report for the short sales data.