What is the difference between Item types such as Amount-based, Area-based and Meter-based, in an invoice template?

In MyGate, an invoice template may include item types of 3 differrent category namey, Amount-based, Area-based, and Meter-based.

Each designed to cater to specific billing needs. Here's how they differ:

1) Amount-Based: This type is used when the charge is a fixed amount, regardless of any other variables. It's straightforward and typically used for items like fixed maintenance fees, one-time charges, or other standard services.
Example: If admin wants to apply same amount for all the flats as monthly maintenance charge of ₹2,000.

2) Area-Based: This type is used when the charge depends on the area or size of the property. It's typically used in scenarios where billing is proportional to the square footage or area of a property.
Example: Maintenance charges calculated at ₹5 per square foot for all the flats, So flat having area 1000 sq.ft. would pay ₹5,000 (5*1000), Whereas Flat area of 2000 sq ft will pay ₹10,000 (5 * 2000)

3) Meter-Based: This type is used when the charge is based on consumption measured by a meter, such as electricity, water, or gas usage. It allows billing according to the actual consumption recorded by a meter. 
Calculation happens based on (Current Reading - Last Reading) * per unit charges.
Example: Electricity charges are based on the number of units consumed at a rate of ₹7 per unit.

Each of these item types provides flexibility in how charges are calculated and presented on the invoice, allowing for more accurate and transparent billing.