Without having seen you bowl, there's more speculation than facts, but here are a couple of possibilities;
A bowling ball goes through 3 defined phases when it's delivered. The first is the skid phase, the second is the hook phase and the last is the roll phase.
Many people who are just beginning to bowl and have a slower speed are rolling the ball pretty much right out of their hand. That's not bad, except the ball will lose kinetic energy down the lane and actually begin to straighten out much too soon. This is because the skid and/or hook phases are too short and the ball's kinetic energy dissipates before the ball makes contact with the pins.
When a person lofts the ball, the skid phase is much longer so the hook phase occurs much farther down lane and the roll phase becomes much shorter also. The ball's kinetic energy will be much greater if you get it into 1-2 or 1-3 pocket.
Additionally, because the hook phase occurs farther down the lane, when the ball does hook toward the pocket, the angle of entry into the pocket is also greater. A ball with a greater entry angle will create more pin action and less deflection than a ball rolling straight down the middle.
Other possibilities would be based on the type of lane you are bowling on, the oil pattern on that lane, the ball you are throwing, how that ball is drilled and how much axis tilt and axis rotation your normal release is creating.
There are many variables that come into play when you throw a bowling ball. Additionally, the combined dynamics of those many variables on any single delivery can change a little or a lot. Each will be something the trained eye would see whereas a newer bowler might not.
Have a friend create a video of you bowling and post it. Something from the back and from the side would allow the Bowling Community see what you are experiencing. We'll have a much better idea then.
Something to keep in mind, many times when a bowler does something different, they get a placebo effect. They bowl better and they want to attribute that increase to the last thing they tried. A day later, doing the same thing may result in terrible results.
It's important to learn solid fundamentals and to learn your own game so that when you do make changes you know if it's you creating the difference or just a few variables coming out different on a different day.
15 lb Storm Hy-Road : 65 x 3-3/8 x 25 500/1000 Grit
15 lb Storm Hy-Road : 50 x 5 x 50 Polished
14 lb Ebonite Cyclone : 50 x 5 x 50 Polished
15 lb Columbia Blue Dot: Circa 1978
325 RPM'a @ 16 MPH