SDCCH on inner zone is not recommended, but yeah, i guess that’s possible (not in alcatel though).
Vand’, in alcatel, the quality HO are available only when going from inner zone to neighbor cells, not inner to outer.
IMO, what is missing is the measurements of the RX_LEV(OUTER) when in the INNER zone, and the measurements of the RXLEV(INNER) when in the OUTER zone. Because of this, the inter-zones HO are based on an assumption of the RxLev in the target zone. In multiband cells, the inner zone (1800) is about 6dB to 10dB weaker than the outer zone (900), but it can’t be known precisely. And that’s a problem…
Plus, you can have different antennas/tilts between 1800 and 900 zones. It further increases the uncertainty of the rx_lev in the target zone (inner or outer).