Please, let's resolve this once and for all. Inland Andy, our resident AS guru has posted that "jack points" fore and aft of the wheels are for jack stands, to be used to stabilize the unit after it has been jacked up via the axle mounting plate rather than the axle tube.
My understanding is that you jack the wheels up off the ground by placing a lifting jack under the axle mounting plate to elevate then secure the unit with jack stands under the ' jack points' so it doesn't fall and squish you while you are underneath the unit.
If the unit is perched on a soft surface such as dirt or sand, the wood 2x4's or 4x4's come into play.
The tongue jack is a leveling device rather than a lifting device, but however you raise the wheels off the ground, jack stands need to be employed to keep the unit in the raised position. If your lifting jack doesn't raise the unit sufficiently, lift it as much as you can, put the jack stands in place, then use the wood blocks under or atop your lifting jack to raise higher and reset the jack stands.
Even if you have a tandem axle unit, backing the unit onto a block to replace a blown tire will give you enogh elevation to change the tire but do you rally want to rely on the "good" tire to keep the unit elevated or place a jack stand under the unit for added safety.?
Am I missing something?