Hi Sampson,
Many factors affect how much your ball will hook. The oil that is applied to the lane is not applied all the way to the headpin, and how far down the lane it goes varys from centre to centre. The further down the lane the oil is applied, the less your ball will hook, in general. There is also a variation in how much oil is applied across the lane - many centres apply a lot in the centre of the lane, and less to none at all on the edge. If most of the oil is applied from second arrow into the centre, for instance, a ball may hook a lot when bowled down the first arrow, less on second arrow, and go almost straight if bowled down the middle.
Another important factor is how many games have been bowled on the lanes since they were oiled. Most oiling machines clean the back end of the lane as they oil, helping the ball to get a good grip and finish strongly into the pins. If the lanes have had a lot of play, the balls can carry oil down the lane, making the back part too slippery for the ball to hook well. Or, after a lot of play, most of the oil may be removed and the ball will start to hook more, but less predictably as the remaining oil is 'patchy'.
It is important for you to learn to bowl over different parts of the lane (different 'lines'), as the best place to bowl on the lane for optimum ball reaction varies greatly from place to place, and even from day to day in the same centre. Try bowling some practice games using the first arrow as a target, then moving to second arrow, then third arrow until you get used to the different ball reactions you get from each line. You will need to adjust your starting position on the approach left or right to get the ball to the pocket on the different lines - the golden rule is, if you are missing the pocket to the left, move your feet left, missing right, move right.
A good coach will help explain all this much better on the lanes.
Good luck.