Data transfer time


I had this problem.
In my program, I send an archive with various data. I send the data using the notification. The central device is a smartphone with Android OS.
If you transfer data up to 10 packets, the smartphone normally receives them and displays the data. If the number of packets exceeds 10, then the remaining packets are no longer accepted, on the 10 packet, data reception is stopped. Data transfer is carried out as follows: after the connection, a timer is started, while the timer is interrupted, data is sent in a for loop. In this cycle, the data of the entire archive is divided into packets and the data transfer function is performed, therefore the delay between packets is minimal. The packet size does not matter, sent packets up to 200 bytes.
In order for the smartphone to be able to accept all packets, you must set a delay of at least 50 ms. before sending each package. If you set a delay with less time, then again the data does not come to the smartphone.

I also tried to send packets using the indication, and in this case, the transmission is normal, because the delay, due to the reverse response from the smartphone about the received data, is 75 ms.

I would like to know why the smartphone can not take a large number of packages? It may be necessary to have a minimum delay between packets or for some other reason.

Chip: BT840F (analog nRF52840);

SDK: nRF5_SDK_15.2.0;

Softdevice: s132_nrf52_6.1.0_softdevice;

Thanks in advance for the answer