Railbus timing

[SilverChased]

I find myself in a situation where I may need to use a railbus this week and found the timings to be suspicious.
https://jp.translink.com.au/plan-your-journey/timetables/bus/t/r620/upward/2024-09-24

The Geebung to Roma Street express railbus only has a single stop and uses the toll road. Yet it says it will take 35 minutes at all times of the day. Does anyone know if this is due to lack of information that the timetable has been set conservatively?

The timing doesn't sound right as there are alternatives routes for me that get there faster without toll roads -- especially to Central. If the timing isn't right, how do we know which connecting services we can make?
I know someone else who normally catches a train (Redcliffe line) who says he will be driving this week due to his commute (Springfield line) being pushed out significantly.

[SurfRail]

Taking an identical route between the north side of Geebung station and Stop 125 at Roma Street by car seems to be about 21 minutes.  It does seem to be a very generous timetable.

[SilverChased]

Route 325 from Geebung to Roma St does 23 stops and takes 31 minutes @ 7:37.

I am going to take this one-stop express toll road railbus to find out what happens in that 35 minute period.

7.14 - Queue to board
7.16 - Bus departure
7.23 - Enter Sandgate Rd
7.32 - Enter M7 Tunnel
7.39 - Outside Normanby station
7.47 - Depart at Roma Street

Observations:
Geebung capark had about 15 spots free whereas it would normally be full.
Heavy traffic at Toombul.
Heavy traffic at Normanby