Why sip in any mutual fund is ok, but averaging a stock that is in nifty 100, is not?

I have read many times that we should not average a stock. Here are few screen shot of MRF and a good mutual fund. Plz look at it and answer my query.
MRF
image

CRISIL NUMBER ! RANKED MUTUAL FUND

MRF MARKET CAP:27693 crore
CRISIL NUMBER 1 RANKED MUTUAL FUND ASSES:2262 CRORE

I am asking this, because i want to invest in MRF on every dip. Is it a good idea?

you should first create a portfolio. don’t put everything in one stock. if you have portfolio already then balance the amount into different sectors. after this you can add stocks in your portfolio on every dip.

In dip should i invest in every 4 stocks of my portfolio.
Suppose i have 4 stocks. Now after every 5% dip should i invest 25% of the invested amount in every 4 stocks. Is that right?
Portfolio are very less volatile as compared to a single stock.
Again why a small mf of 2k crore is ok for averaging a stock that has market cap of 27.5k crore it not?

you have to invest in the stock which has fallen. if all the stocks fallen then you need to wait for a day or two to invest.

your portfolio should have one more Row called Cash in Hand. cash in hand should be at least 20% of portfolio at any point of time.

buy on dips means you should see dip in individual stock not dip in portfolio.

MF I dont know anything.