  We performed a theoretical analysis on the relevance of the small frequency
separation $\delta \nu$ in determining stellar ages, masses, and radii. We
adopted the SCEPtER pipeline for low-mass stars, [0.7, 1.05] Msun. Synthetic
stars were generated and reconstructed assuming different relative precision in
$\delta \nu$ (5% and 2%). The quantification of the systematic errors arising
from a mismatch between synthetic stars and the recovery grid was also
performed. The biases were negligible. The statistical error in age estimates
was strongly dependent on the stellar evolutionary phase. It is at its maximum
at ZAMS and decreases to about 11% and 6% ($\delta \nu$ at 5% and 2% level)
when stars reach the 30% of their evolutionary MS lifetime, then vanishes in
the last 20% of the MS. For mass and radius estimates we detected nearly
identical behavior for an observational uncertainty of 5%. No benefit was
detected for mass and radius determinations from a reduction $\delta \nu$
precision to 2%. The impact on the age of the initial helium abundance resulted
in negligible results. On the other hand greater bias (2% and 1%) in mass and
radius estimates were detected whenever $\delta \nu$ is in the observational
pool. This result, together with the presence of further unexplored uncertainty
sources, suggest that precision in the derived stellar quantities below these
thresholds may possibly be overoptimistic. [...] Finally, we compared the
estimates by the SCEPtER pipeline for 13 Kepler asteroseismic LEGACY sample
stars with those given by six different pipelines. Overall, on the LEGACY
sample data, we obtained a multi-pipeline precision of about 4.4%, 1.7%, and
11% on the estimated masses, radii, and ages, respectively.
