Yes, it will show combined as 200 shares @ an average price of 905 (900+910), But SL-M order will be 2 separately for both the orders, as it is not possible to modify the existing pending order.
Yes you bought 200 shares at an average price of 905, that doesnt mean the orders will be clubbed together into a single SELL order, Your sell order stop losses will be different for both orders, in case you would like to modify the stop loss values into a single one, you can edit and modify the same individually. Try using Z5 to do that. Other platforms may not allow you to modify.