  We compared the results from the JSOC pipeline for horizontal flow components
and the perturbations of the speed of sound at set of depths with equivalent
results from an independently implemented pipeline using a different
time-distance inversion scheme. Our inversion pipeline allows inversion for all
quantities at once while allowing minimisation of the crosstalk between them.
This gives us an opportunity to discuss the possible biases present in the JSOC
data products. For the tests we used the subtractive optimally localised
averaging (SOLA) method with a minimisation of the cross-talk. We compared
three test inversions for each quantity at each target depth. At first, we used
the JSOC setup to reproduce the JSOC results. Subsequently, we used the
extended pipeline to improve these results by incorporating more independent
travel-time measurements but keeping the JSOC-indicated localisation in the
Sun. Finally, we inverted for flow components and sound-speed perturbations
using a localisation kernel with properties advertised in the JSOC metadata. We
successfully reproduced the horizontal flow components. The sound-speed
perturbations are strongly affected by the high level of the cross-talk in JSOC
products. This leads to larger amplitudes in the inversions for the sound-speed
perturbations. Different results were obtained when a target function localised
around the target depth was used. This is a consequence of non-localised JSOC
averaging kernels. We add that our methodology also allows inversion for the
vertical flow.
