struggling with two formulas

Hi I'm struggling with two formulas support wont provide support on, and wondered if anyone can help me out.

1) Return sales orders where the total number of line items is equal to or greater than 9 and a custom column field (creates job) in respective line items equals 'Yes'.

I'm thinking this should be:

'Formula Numeric'

CASE WHEN (({custcol_job_isjob} = 'Yes') THEN COUNT({custcol_lineid}) ELSE 0 END

Note I can't use SUM as custcol_lineid can be greater than 1

2) Return sales orders where a line item is deleted from the sales order.

Does anyone know if there is a field that holds the total count of line items on a sales order? I assume comparing this fields old and new value would work i.e.  formula numeric Field * Systemnotes.oldvalue>Systemnotes.NewValue?