Two-factor calculation (quantity and duration) for the estimate

Users want to be able to perform cost calculations using two measurement variables simultaneously, such as quantity and duration. This need is particularly common for equipment or scaffolding rentals (e.g., 4 casters rented for 2 months at $19/month, or pricing calculated in months/feet) as well as for specific fees (e.g., $7.50 per 8-foot unit per month). Currently, users must resort to complex workarounds involving custom formulas (variables enclosed in curly braces or single quotes) or manually moving certain items to the “Equipment” category. A native feature would greatly simplify the entry of these two-factor estimates.