Unable to reimport same tiling in 2.5D ortho process.
Reason to reimport is that 2.5D process creates better looking orthos than from 3D. 3D orthos have too much artifacts. Also 2.5D process has unique retouching tools not available in 3D. No need to have same tiling just ROI.
As workaround to "tiling mode is not supported in 2.5D reconstruction" it is at least possible to import definition(.recons) from 3D reconstruction. Also it helps import rectangle ROI aligned to GCS axes which for some reason was removed from 2.5D framework.