Newbie question about funds workflow on CnC purchase orders

I am fairly new to Zerodha, and I have a question about how the workflow of funds is supposed to happen when we do CnC purchase orders.

Suppose I buy 10 shares of company X at Rs.100 each, in CnC mode. The “margin preview” feature tells me that I need to have Rs.1000/- as margin with Zerodha to make this purchase happen. So I transfer Rs.1000/- via UPI (so all of that Rs.1000/- reaches my account), and buy 10 shares of company X at Rs.100/- .

Now, there are some charges for this purchase which are not included in that Rs.100/- per share, such as STT, exchange fees, and so on. Suppose this comes up to Rs.10/-, so that the total amount that I have to pay Zerodha for this purchase is Rs.1010/- .

I have the following questions:

  • When does this extra Rs.10/- become due?
  • How will I know that this Rs.10/- has become due? Will I get an email asking me to pay this extra amount?

I could not find this information anywhere on Zerodha. But I did find here that if my available cash balance is negative then I will be charged interest @18% per annum. I want to avoid paying this interest, which is why I am concerned about knowing my dues up front.

I actually purchased some shares a couple of days ago. Here is what I see (suppose the extra dues are Rs.10):

  • My “Available cash” on the Kite dashboard is positive Rs.0.01, not negative Rs. 10.00 . So as per Kite I am not required to pay this Rs.10, yet.
  • But: as per Funds->Overview on Console, my Closing balance is negative Rs.10.00.
  • I haven’t got any notification asking me to pay the Rs.10.00 .

Which of the two values (“Available cash” on Kite, and “Closing balance” on Console) should I go by, to figure out if I am already being charged interest @18% PA?

Will I get an email or any other indication when it is time for me to pay this Rs.10.00, before the interest kicks in?

For now, since I have done purchases on only one day, I can go look in the Contract Note for that date to see how much I owe. Are we really supposed to keep track of the dues (and how much we paid) using a separate spreadsheet, update the sheet as soon as each Contract Note comes in and for each payment we make, so that penal interest does not kick in?

This is bothering me a lot, and keeping me from doing additional purchases. I don’t like paying penal interest by default.

P.S: I raised a ticket for this, but I got back a useless response detailing the breakup of the Rs.10, which I already know! What I don’t know is when I am supposed to pay this Rs.10, and whether I will get an email asking me to pay my dues. The support executive was unable to help me with this. Hence this post, in the hope that seniors here will know this workflow from their experience.