Zerodha Mutual Funds subscription fees in case of demat with zerodha

Hi I have demat account with zerodha with AMC charges applicable, so I need to pay Rs 50/- separately for mutual funds holdings

Rs.50 PM is the subscription fee for investing through Coin. It is applicable only once your total investments cross Rs.25000.

is it applicable monthly or yearly

and what would be the total AMC charges,ie
300+50= 350
300+(50*12)= 900

900…300 AMC + 50x12 subscription fees once your total investment crosses 25000

Monthly fee of Rs.50+service tax.