After rebalancing or Manage order which involves both Buy and Sell order, your current investment will change. During rebalance, some stocks might have been sold and the investment made on these stocks would have also been removed from your current investments. And hence the change.
At any point, the current investment gives you the sum of Qty and Average Buy Price of all the stocks that you currently hold. To check on the total amount you have invested so far, please check the Money Put In of each smallcases.
The P&L would be updated in the Realized returns and not in the Current Investment.
Say you bought HDFCBANK for Rs.10000 and sold it for Rs.11000 / 8000. Now your realized returns will be Rs.1000. (-2000 if loss) and Rs.10000 will be removed from your Current Investment. But this will be saved as Money Put In value. Hence you’d see your Current Investment has decreased. Hope this clarifies.
In rebalance and Manage order where both buy and sell order is involved, the sell orders are executed first. With the amount realized from selling stocks, the buy orders are getting executed.
In this scenario, if the Sell amount > Buy amount, the extra amount will be credited back to your Zerodha funds. Only if the Buy amount > Sell amount, the additional amount will be debited from your Zerodha funds. And this additional amount is being added to your Money Put In, not Current Investment.