Confused about improvements for 101/23 freeways

I've been watching the work being done on the 23 and 101 freeways, and I'm very confused.

On the 101, temporary barriers are being placed close to the center divider and the guard rails are being removed. Once removed, a cement median will be constructed.

I'm assuming that the cement median is "better" and that's why the current structure is being replaced.

Moving to the 23 Freeway where lanes are being added and a center divider is being built: The barriers already exist for creating the new lane(s), but the metal and wood guard rails have been installed. Why?

I can just imagine in a few years that taxpayers will need to pay for the placement of the temporary barriers, the cost for removal of the metal and wood guard rails, the cost of putting a cement median in--all of this after paying for the original metal and wood--and then the cost of removing the temporary barriers.

Am I missing something here? Dave Eng Thousand Oaks