scale ${p_\text{typ}}$ and leaves no window ${\overline{\Lambda}_{\slashed{\pi}}}\gg
k\gg|k_0|\approx100\;{\ensuremath{\mathrm{MeV}}}$, while the [N${}^{2}$LO]{} fit at both $k=0$ and $k_0$ does not suffer this limitation.

[**Fitting in a Region**]{} The issue is less transparent when the LEC is not determined by exactly reproducing some data, but by least-$\chi^2$ fitting over a whole region in $k$. That is the typical case in $\mathrm{NN}$ scattering; see e.g. Ref. [@Epelbaum:2014efa]. The deviation of the fitted result from data is more regular at any given cutoff $\Lambda$ than when it is exactly zero at $k_0$. A pronounced spike is therefore replaced by a more uniform behaviour inside the fit region. The comparison between two cutoffs in eq.  is therefore also more uniform as a function of $k$. Since cutoff variations can now be balanced by adjusting LECs, the coefficients ${\mathcal{C}}_n$ are artificially small in that régime. One still expects the cutoff dependence to decrease order-by-order, but the characteristic slopes are harder to see since the observable is constrained by the fit. Just like in the neighbourhood of a fit point, an observable will first have to shed the fit constraints outside the fit region for pronounced slopes.

Such a fit region must of course be inside the 