The combinations signature has been tested enough:
We have many official functions where the combinations signature is proposed.

• pgr_aStar
• pgr_aStarCost
• pgr_bdAstar
• pgr_bdAstarCost
• pgr_bdDijkstra
• pgr_bdDijkstraCost
• pgr_dijkstra
• pgr_dijkstraCost
• pgr_dijkstraNear
• pgr_dijkstraNearCost
• pgr_KSP (all signatures)
• pgr_boykovKolmogorov
• pgr_edmondsKarp
• pgr_maxFlow
• pgr_pushRelabel
• pgr_trsp Related to Make official all the TRSP family of functions #2701
• pgr_trsp_withPoints Related to Make official all the TRSP family of functions #2701 & Make official the WithPoints family of functions #2700
• pgr_withPoints Related to Make official the WithPoints family of functions #2700
• pgr_withPointsKSP Related to Make official the WithPoints family of functions #2700