The 'spin-only' magnetic moment for $$\mathrm{Mn}^{7+}$$ is $$0$$ BM. During the titration of $$\mathrm{KMnO}_4$$ with oxalic acid in an acidic medium, manganese is reduced to $$\mathrm{Mn}^{2+}$$, which has a 'spin-only' magnetic moment of $$5.91$$ BM.

Thus, the difference in magnetic moment values is calculated as follows:

$$0 \, \text{BM}$$ (for $$\mathrm{Mn}^{7+}$$) subtracted from $$5.91 \, \text{BM}$$ (for $$\mathrm{Mn}^{2+}$$), which results in $$5.91 \, \text{BM}$$.

Rounding this to the nearest integer, we get a difference of approximately $$6$$ BM.