B/X Clerics

I have been playing a lot, but have been very unmotivated to edit my book of divine magic. Writing is done, but I enjoy the creative part of design much more than making sure the details are right. Of course I don’t feel good about publishing something, even something for free, if it is not perfect.

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 3^rd level and 4^th level spells at the same level, 6^th. 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 subject
http://rpg.stackexchange.com/questions/7885/why-do-clerics-unlock-3rd-and-4th-level-spells-at-the-same-experience-level

I am pretty sure I never played a B/X cleric above 3^rd level.