I added another project to the mix, involving something I have wanted for a long time involving B/X D&D. Today I noticed something I have never seen before.
Clerics gain access to both 3rd level and 4th level spells at the same level, 6th. A level later they get 5th level spells. that's a big power jump.
See the chart below curtsey of my scanned copy of the Expert D&D rules I purchased from Drivethru. I checked my print version and it is the same.
This guy did a lot more research than I did on the subjectI am pretty sure I never played a B/X cleric above 3rd level.