I'm inclined to agree with the figures and what others have said with the story behind them.
Since Merlin are no longer a PLC, they're not hamstrung by having to report these things accurately in the public domain. So they could well have included all second gate admissions in that figure, but I doubt they've changed how they are reporting these numbers since then. Bearing in mind that they are being published to argue the case to planning authorities for new attractions and their impact on attendance. Cooking the numbers all of a sudden wouldn't help achieve that.
I have doubts that that's purely for the park itself, but I'm happy to be proven wrong. Merlin would have had to report to their shareholders how they calculated these numbers in the PLC days, so does anyone know if that included second gate back then?
If it does include second gate, it's only in recent years that they've been giving away free golf with hotel stays. These numbers would have also included the spa.
It wouldn't surprise me if park attendance was higher in general either due to the £80 pass. As a fellow previously off-peak regular like
@rob666 I concur that there haven't really been many true off-peak days since 2022. Some of the terrible queues due to poor operations have masked this, but general pathways and the car parks feel much busier than they used to. Not having entertainment and having 6 hour days was always the off-peak trade off, partially made up for with walk on rides and no wait for food. Now it's just miserable, where you still have 6 hour days but have to wait 20-45 mins for all the rides, queue for the Monorail, and hike around without a Skyride. You can't even enjoy some food anymore.
Pile 'em high and flog 'em cheap, the seemingly terminal downgrading of Alton Towers continues.