Lalpathlab insider activity

There was a insider activity on 29th October but Total buy value is showing ZERO. If you check
history also it shows all buy value zero (99%) but it shows sell value. What could be the reason why insiders are not disclosing buy value?
August 13 & 16 there was a insider activity with Zero Buy value But stock shoot up 11% from there buy value. If you do back test it might be the same. Now also there is a insider activity & Stock is at Demand Zone as this script is fundamentally good to have in our portfolio(I am also holding).
Refer below charts as well insider activity for more understanding .