Looks like I didnt make myself clear enough. Not your fault, viper, its on my bad English.
What i wanted to say is:
When you hit the tank, say, 10 times in a row, you only see 7 messages, cuz the 3 older messages are deleted from the screen. If you pause, other messages appear. When you engage and shoot again, your screen shows again your hits. Say, if you hit it again, 20 times more, you will believe only 7 landed, cuz the text on the screen doesnt seems to change... but it actually CHANGES!
Think about it: 7 hits, 7 lines saying "you've hit Pedrinho". At the 8th time you hit me, the oldest line disappears, and a new one is written - but since all lines have the same words, and there is no animation showing the lines "going up", you cant tell when the screen updates every new line of text - unless you STOP SHOOTING, giving the servers time to show another line of text from other players actions.
Believe me, I had the same reaction the fist time I played on this new update versiom (on which tanks need way more hits to die).
So, keep shooting, dont worry about what texts are being shown on the screen, and only stop when they die - or when they blow your nose.
Edit: about your info regarding hits not being registered on screen after a line of text from other players actions, its caused by lag, rest assured.