Demand cost after correction:

New reactive power $($kVAr$1\text{'})$ for the $1^{st}$ six months $(200$kVAr $)$

New total power $($kVA$1\text{'})$ for the $1^{st}$ six months $(825$kVA $)$

New reactive power $($kVAr$2\text{'})$ for the $2^{nd}$ six months $(34$kVAr $)$

New total power $($kVA$2\text{'})$ for the $2^{nd}$ six months $(701$kVA $)$

New annual demand cost $($$$164,748)$

Annual saving $($$$32,194)$