Sahih Muslim records a path through ‘Ubayd Allah b. ‘Umar ← Nafi‘ ← ‘Abd Allah b. ‘Umar with the wording «فَاقْدُرُوا ثَلَاثِينَ» (“reckon thirty”). This path reaches the same Companion through Nafi‘ rather than Malik.
It does not directly corroborate al-Shafi‘i at Malik's level; it is another partial mutaba‘ah. One Companion's teaching may be reported through distinct pupils, and related meanings may remain mutually supportive although the precise wording differs.
The explicit number “thirty” also matters when comparing «فَاقْدُرُوا ثَلَاثِينَ» with the shorter «فَاقْدُرُوا لَهُ». Every wording needs to be read in its fuller transmission context.