Cost Efficiency of Store Potions/Casks/Kegs

Question

Im curious as to the cost effectiveness of using store bought potions on a new server, And when the cutoff would be when you would start using the in game npc store.

Small Manas -  

125 for 6 tc  Cost in shop = 56 gp each or 7,000 gold for 125 @ npc

300 for 12tc cost in shop = 56 gp each or 16,800 for 300 @ npc

Strong manas -

100 for 7 tc cost in shop = 93 gp each or 9,300 @ npc

250 for 17 tc cost in shop = 93 gp each or 23,500 @ npc

Great manas -

100 for 11 tc cost in shop = 144 gp each or 14,400 @ npc

250 for 26 tc cost in shop = 144 gp each or  36,000 @ npc

Ultimate manas

100x for 33 tc cost in shop = 438 gp each or 43,800 @ npc

250 for 79 tc cost in shop = 438 gp each or 109,5000 @ npc