[solved] - Tooltips: cost of extension building should be cst_multiply_post
simutrans v100.0 & r2153
On the toolbar tooltips, cost of extension buildings show cost of generic_stop.
It should be cst_multiply_post.
A patch attached.
COST_CONSTRUCTION in wkz_station_building_aux
sp->buche(umgebung_t::cst_multiply_post*besch->gib_level()*besch->gib_b()*besch->gib_h(), pos, COST_CONSTRUCTION);
[edit]
One more problem, cost of airstop is not cst_multiply_airterminal but cst_multiply_station.
updated patch.