What do we find?

You assume that the comparison is based on similarity. But it is possible that comparison is a measure in the Torah that anything that is sufficiently similar can be studied. Therefore, one can study 2:1 and 3:4. Even if in the end there is not sufficient similarity. We find something similar regarding the city of gold. The Gemara in P. Thulin says that we do not find a disagreement from end to end, meaning that one requires sin and the other says it is permissible. There is a threefold disagreement presented, in which one of the Tannaim says it is permissible and the other requires sin. The Gemara rejects the fact that there is a third Tannaim that says it is forbidden by the rabbis, and in this there could be a disagreement from end to end. A more extreme example is given in the KH”I on a builder with tools named Ra”z Meltzer in an article. A builder is a group of parts to create a space (building a house from wood or stones). One consequence is the creation of a space not by grouping parts – a tent. A second consequence is the grouping of parts without creating a space – a mop. This is more extreme, because when you look at the relationship between a tent and a mop (the two consequences) you will not see any similarity between them, even though they are both the consequences of a builder. The similarity between them passes through the father of a builder.