You're Correct!

When it comes to maximizing your distance and producing an efficient, consistent ball flight, centred strike is a key component.

You can produce more distance with a slower swing speed with a centred contact than an increased club speed with an off centre strike. When you find that you are striking your irons very inconsistently, there must be a lot of manipulation and timing being relied on to find the ball on the face, never mind the centre of the face.

There are two kinds of inconsistent strikes. There is fat and thin contact and also heel and toe strikes.

Fat and Thin
If the club head is bottoming out before the ball then you will have a tendency to hit both fat and thin shots. When this occurs, the player is usually either hanging back on their trail leg at impact or casting the club with their wrists which makes the low point of the swing behind the ball. Try getting your weight forward and the handle of the club leading the club head.

Toe and heel
When the club is inconsistently being struck out of the toe and heel there is a club path issue. The clubs path is either moving too severely across the ball at impact or being manipulated with the hand action. If the club is working too much on an out to in or in to out path, the result will be a glancing path across the ball at impact making it difficult to find the centre of the club face on a consistent basis. If you are out of position during the down swing, you will also likely be using the wrist and arms to manipulate the club head to find the ball at impact adding to the inconsistency.

Work on bottoming out the club consistently while correcting your club path and maintain those wrist positions through the shot.

Having too flexible shafts in your irons will have a slight effect on where you strike the ball on the club face but not enough of an effect to cause massive deviation with your ball striking. Too flexible shafts will cause inconsistent ball flights with inconsistent spin rates and launch conditions.

You have probably heard this many a time when a player thins or tops a ball. Their expert friend offers the advice of You lifted your head. It seems this head lifting is the root to all problems! Most people dont lift their head at all. Those thins and tops are usually due to weight being too much on their trail side and they then have to flex their arms and wrists so the club doesnt crash into the ground before hitting the ball.

Inconsistent strikes can occur from cutting across the ball but this is not the sole reason for an inconsistent strike pattern. There are many reasons why you could be struggling to the find the centre of the club face on a consistent basis. Anything from being too much from the inside, too much from the outside, weight being in the wrong place or inconsistent wrist and arm positions could cause an irregular ball to club contact.