Short answer: Because of vinay (reverential etiquette). In Jain tradition, the Khamāsamano (Pañchāṅg‑praṇipāt) is done:

• three times to Deva (the Jina/Tīrthaṅkar), and
• two times to Guru (Āchārya/Upādhyāya/Sādhu).

This expresses the proper hierarchy of the Pañcha‑Parameṣṭhi: the Jina is the highest, so He receives the greater number; the Guru is deeply venerated as the living guide to the path, hence two salutations.

Notes by tradition:

• Śvetāmbara (especially Mūrtipūjak) practice explicitly follows “3 to Deva, 2 to Guru” during darśan/vandan.
• Digambara tradition equally upholds strong Guru‑vinay; the exact physical count can vary by local ācāra, but the principle of giving the Jina the highest reverence remains the same.

For the Khamāsamana sūtra text and simple meaning, see this reference: