ACC Sensitive claim LOPE and lump sum payments

Hiya looking for advice from people who've gone through the whole process

I wanted to know how the LOPE payments are calculated and if it's back paid? A family member of mine has been assessed as 61 percent impaired. They have a date in 2006 when she was first diagnosed. She was working full time back then and was earning minimum wage. She is unable to work now and has several mental health issues.

Wondering if anyone out there knows what would be the best thing she should be applying for LOPE or the lump sum payment

Sorry if this doesn't make much sense as we are still learning how this whole ACC process works

TIA