It is a fact that all conditions simultaneously burn oil off the heads and carry some down as they transition.  Longer buffs can make carrydown relatively unnoticeable, but no amount of head oil can lesson the impact of early burn.

Good example is nationals.  On the 43 foot buff in the team event everyone is forced to go a bit straighter right out of the gate.  You don't really notice the carrydown, because you aren't playing the back ends, but, are playing a track that is developing as the heads break down.  Scores are high in the team event beause the transitions are simpler.  On the shorter pattern, transitions are tough in the doubles because there is some back end out of the gate.  However when people try to use it they get both a carrydown impact and burn in the heads during transitions.  Scores are very low in doubles.  By singles, the transitions have settled down, and the shot has opened up to where guys can get left and swing the ball.

Carrydown is real, but the impact is temporary at most, and not really a factor on long buffs.

If you guys are talking about everyone using reactive resin balls, then, yes, it's more than likely that just the head oil has been depleted.

But, I guarantee you when there's open bowling  or a women's league, before our league, then we have both head oil depleted and carrydown. Those plastic balls and house urethanes definitely remove the head oil and deposit some of it further down lane.

I definitely agree with the plastics moving oil, but when a ball is reviewed, chances are pretty good that they tested on a fresh oil shot and lanes transitioned. Would bet they did not drill and go and tell them to turn on a lane that has been bowled on by open bowlers all day so they can test a ball.

A majority, no matter ability, truly do NOT understand ball motion or reaction...they tend to throw and as soon as adjustment is needed most have little idea of what actually to do...most of this has been created by 'patterns' as bowlers are told how to attack a condition...nothing on transition or change...thus the bowler is fine until there is any adversity
I have worked with bowlers where they could strike and/or hit the pocket (on a THS by themselves) for literally 30 mins...as soon as they see over reaction, they go to the bag instead of understanding how to move or chase a condition
Bowlers do not understand angles and what honestly creates them along with reaction
At the mini eliminator one year, we actually graphed the lane at different stages of the days...you'd be surprised at how little conditioner would 'carry-down' the lane...in an event such as that, it was the amt residual friction that effected the reaction, as the conditioner would dissipate more than anything creating different lay down areas or more of a diamond effect...the fronts would go, there'd be conditioner still built up in the middle and friction down lane thus creating different angles...it was the lane more than anything
When you have the proper ball in your hands you never see 'carry down'
The reason for straighter angles at natls is more so cliffed back ends....little buff...the more the fronts go, the more the angles increase and the players are forced inside, the become very sensitive...better straighter angles

Watch as the ball enters the pin deck and exits it...that tells you what the ball is doing