I don’t know the format of the data you are using. And untill I understand this format i can’t help you with more specific answer.Sorry!
Reading your words I suppose you calculate the BHCA – I think tahat this value must be measured from some kind of equipment or software.
From my experience I don’t calculate BHCA I have them measured and use them without making any effort.
One of the reasons for increasing the number of call attempts is that your network is working with very high GoS and one subscriber is making several call attempts to make a conversation – I don’t think that it’s true. I advise you to check the method for calculating the BHCA.
With the other question – Yes these times are correct, but I still think that so few subscribers cannot make so many call attempts in an hour. Check again your queries.
Is the number of the subscribers corresponds to the number of the call attempts?