MEC is considered with most profitable capital asset, whereas MEI is concerned with the amount investment undertaken in some investment project.
MEC is a stock concept, while MEI is a flow concept
In the concept of MEC, the supply price or replacement cost of the capital asset is kept into consideration, whereas in the concept of MEI, the outlay on investment project or the cost of financing project is kept into consideration.
The variables to determine the MEC are on the other hand in case of MEI schedule the variable are investment and
In case of MEC schedule the rate of interest and price of capital asset remain the same. On the other hand in case of MEI the rate of interest does not same.