Is the ruling regarding the transfer of intention from solo worship to leading (Imamah) the same for obligatory and supererogatory prayers?

Primary text

The principle is that the obligatory prayer should equate to the supererogatory prayer regarding the intention (Niyyah). The evidence of Jabir and Jabbarah in the obligatory context strengthens the allowance for transferring the intention to lead. This transfer is permissible because necessity calls for it, similar to the situation of deputizing an Imam (Istikhlaf). If a person praying alone has others join and he continues leading, stopping the prayer to explain the situation would be blameworthy, violating the prohibition against invalidating deeds (Quran 48:33). Continuing the prayer and then informing them of the invalidity of their prayers would be even worse.