The description of the plane shift spell (PHB, pg. 266) says:
You and up to eight willing creatures who link hands in a circle are transported to a different plane of existence. You can specify a target destination in general terms, such as the City of Brass on the Elemental Plane of Fire or the palace of Dispater on the second level of the Nine Hells, and you appear in or near that destination. If you are trying to reach the City of Brass, for example, you might arrive in its Streets of Steel, before its Gate of Ashes, or looking at the city from across the Sea of Fire, at the DM's discretion.
The spell's description singles out a location on a layer of the Nine Hells that is not the first (Avernus), which implies that you can use plane shift to teleport from another plane (i.e. not the Nine Hells) directly to a specific layer of the Nine Hells.
However, in the DMG (pg. 64), under the heading "The Nine Layers", it describes Avernus as follows:
No planar portals connect directly to the lower layers of the Nine Hells, by Asmodeus's orders. As such, the first layer of Avernus is the arrival point for visitors to the plane.
This implies that you cannot go directly to any layer of the Nine Hells other than Avernus. In the plane shift description, it says "you appear in or near that destination", which given this quote from the DMG, might mean that, because you might not be able to get directly to the second layer of the Hells, you arrive "near", meaning Avernus. The last sentence of my plane shift quote expands on the City of Brass example, but not the palace of Dispater example.
However, the DMG quote also describes portals specifically, so this might not apply to plane shift since it doesn't explicitly mention a portal.
Can you plane shift to any layer of the Nine Hells besides Avernus? In other words, does this DMG quote prevent you from plane shifting to, say, "the palace of Dispater on the second level of the Nine Hells"?