You are entitled to deduct brokerage costs.
CG section, in full value under consideration, have I to mention the sale value after deducting the losses occurred?
You have to mentioned the "Sale Value" of Shares.
In the Cost of acquisition, you have to mention how much you paid to buy the shares [including brokerage during buy].
In the Expenditure you have to mention the brokerage for sell.
Brokerage was paid @ 0.2%, but without any proof.
Not sure I understand this, why don't you have proof.
If I mention brokerage values, will be any problem due to lack of proof?
Generally proofs are not asked while filing returns. However there can be an enquire on the calculation and one would have to produce proofs. Note the enquire can also ask for evidence on the total sale price or buy price and not just brokerage.
Further read at Income Tax India
Every Switch is considered a taxable event. So for example you invested x units at Rs 5000. After 6 months, you switched. Say you got Rs 5500 and bought y units for same funds [say growth to dividend]. Then you again after 6 months you switched to grown, the price was Rs 6000. Then sold it after one month for Rs 6100.
Total sale was Rs 5500 + Rs 6000 + Rs 6100
So your total initial investment is Rs 5000 + Rs 5500 + 6000
Your Total gain taxable will be Rs 1100.