  Following the previous research on epicyclic oscillations of accretion disks
around black holes (BHs) and neutron stars (NSs), a new model of high-frequency
quasi-periodic oscillations (QPOs) has been proposed (CT model), which deals
with oscillations of fluid in marginally overflowing accretion tori (i.e., tori
terminated by cusps). According to preliminary investigations, the model
provides better fits of the NS QPO data compared to the relativistic precession
(RP) model. It also implies a significantly higher upper limit on the Galactic
microquasars BH spin. A short analytic formula has been noticed to well
reproduce the model's predictions on the QPO frequencies in Schwarzschild
spacetimes. Here we derive an extended version of this formula that applies to
rotating compact objects. We start with the consideration of Kerr spacetimes
and derive a formula that is not restricted to a particular specific angular
momentum distribution of the inner accretion flow, such as Keplerian or
constant. Finally, we consider Hartle-Thorne spacetimes and include corrections
implied by the NS oblateness. For a particular choice of a single parameter,
our relation provides frequencies predicted by the CT model. For another value,
it provides frequencies predicted by the RP model. We conclude that the formula
is well applicable for rotating oblateness NSs and both models. We briefly
illustrate application of our simple formula on several NS sources and confirm
the expectation that the CT model is compatible with realistic values of the NS
mass and provides better fits of data than the RP model.
