about Hall count (tacho value) problem

Hi, I'm using vesc50A for my robot project using CAN communication.

When I get the tacho_value from CAN status (config. CAN_STATUS_1_2_3_4_5), sometimes data doesn't updated.

I'm reading the CAN status data 50Hz and the "CAN status rate" of VESC is 50Hz. The motor has 10pole, and 5.4 gear ratio, Hall sensor.

If I running the motor with same rpm, I should get the gap of tacho values not zero, but sometimes, the gap is zero, and this means that I got the same tacho value.
ex.)
--> 10 20 30 40 50 60 70 80 90 100 ...(tacho_value what I expected)
--> 10 20 30 40 40 50 60 70 80 90 ...(tacho_value what I got.)

In my opnion, if the tacho value in the VESC doen't updated when I get it from CAN, the next time tacho value should be updated with last value.
ex.)
--> 10 20 30 40 50 60 70 80 90 100 ...(tacho_value what I expected)
--> 10 20 30 40 40 50 60 70 80 90 ...(tacho_value what I got.)
--> 10 20 30 40 40 60 70 80 90 100 ...(tacho_value in my opinion)

Can I use this tacho value like encoder value?