For the conversion different basic assumptions can be used and each of them renders different results. So, the final outcome is not unambiguous. For instance, for the conversion of the soprano in Bb to Eb the length of tone hole nr. 6 was compared to the length of the same tone hole in the alto. This large tone hole is the lowest one the location of which can be measured with a resonable accuracy. Toneholes located in the bottom bow are far harder to determine the exact location of. This yielded a greatest acoustical length (for a written low B) of 1209 millimeter. From this alone it appears that something is not quite right, because the acoustical length of a written low B on an alto in Eb is approximately 1178 millimetre at a concert pitch of A=440Hz; 1193 millimetre at a concert pitch of A=435 Hz. So, the converted soprano tends to show too large compared to the alto, which is especially noticable in the size of their respective truncations. On the other hand, the real value of the 24495 alto's acoustical length is 1224 mm. The instrument seemes to be tuned to a slightly lower concert pitch.

Thus the profiles are only comparable rather loosely, as a characterization of bore shapes and not more than that.