It really hard to tell without seeing your approach.
Is speed measured at the pin deck? If so, perhaps your ball is slowing down due to more friction. Are they putting less oil down? Are you using more surface? Are you playing closer to friction on the lanes?
Having said all that, each ball needs to slow down, somewhat, in order to change direction and deflect (some) going through the pins.
Does the speed of your arm swing and foot speed match? Yes, you can increase ball speed with quicker feet, as long as your timing is still good. How is your carry?
Ball speed is measured at the pin deck. Two houses, one synthetic and one wood. Within .5 mph at both houses resulting in 1.5-2 mph drop overall. No additional surface on equipment.
They may be using less oil in the synthetic house but I don't have confirmation. Just basing that off of lane play lately versus last season. The wood house is 38ft buffered to 44 with 22-24 ml's (can't remember which volume amount) but that's the same as last season.
I want to say carry is down but I've been in a slump on my scores the last 4-6 weeks. I'll go from leaving 9 pins to 7's and 10's in one game, same ball, same line (as repeatable as I can be lately at least).
I feel that my timing is one thing that's actually going well right now. I used to be a bit late on timing and had to muscle the ball a bit down and squeezed. I recently changed span, pitches, and started adding a single piece of bowlers tape to the back of the thumb. No more squeezing and timing feels right but ball speed has dropped and so moves on the backend can be a little more check mark than desired. I certainly do not have high axis rotation, but now essentially being more rev dominant, I've had to start left where I used to end the night at.