That is a correct assessment.
However, a word of caution is in order: don't forget that ships' capacities can be different. Assuming that the Asterix and the joint support ships are equivalent to the needs of the Royal Canadian Navy, then purchasing the Asterix as soon as possible is a much less expensive option than building the two joint support ships. If two ships are desired, then purchasing the Asterix and the Obelix is a much less expensive option than building the joint support ships.
As I said, this assumes that both types of ships adequately meet the needs of the Royal Canadian Navy. Do they? This question can be answered by the Royal Canadian Navy's marine armament and equipment specialists.