  It has recently been proven that the invariance of observables with respect
to angle dependent phase rotations of reaction amplitudes mixes multipoles
changing also their relative strength [1]. All contemporary partial wave
analyses (PWA) in $\eta$ photoproduction on protons, either energy dependent
(ED) [2-5] or single energy (SE) [6] do not take this effect into
consideration. It is commonly accepted that there exist quite some similarity
in the $E0+$ multipole for all PWA, but notable differences in this, but also
in remaining partial waves still remain. In this paper we demonstrate that once
this phase rotations are properly taken into account, all contemporary ED and
SE partial wave analysis become almost identical for the dominant $E0+$
multipole, and the agreement among all other multipoles becomes much better. We
also show that the the measured observables are almost equally well reproduced
for all PWA, and the remaining differences among multipoles can be attributed
solely to the difference of predictions for unmeasured observables. So, new
measurements are needed.
