Can I get a repricing on this 3.5 custom magic item?

[Oryan77]

This item is meant to be a 1-use item, like a tanglefoot bag or alchemist's fire. Right now it is priced as if it is usable once per day. Can anyone price this sphere out using all of the statistics but make it a 1-use items rather than reusable per day?

Here is the custom item in question:

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Serpent Sphere:
This golden sphere is etched with carvings of serpent like heads. Once per day, as a full-round action, the sphere may be tossed with a range increment of 10 feet and floats perfectly in the air. The sphere sprouts 1d6 enormous snake heads which writhe about in the air. Each head may make a single attack against a foe within 10' with a +10 bonus that deals 1d10+4 damage. After this attack, whether it hits or misses, the head crumbles to dust.

Moderate Conjuration; CL 11; Craft Wonderous Item, Summon Monster 6; Price 26,400

[TuggyNE]

Using the guidelines, we reverse 1/day by multiplying by 5, then command word by dividing by 1800, and finally convert to single-use-activated by multiplying by 50. The result is 3666.67, or roughly 3650gp.

Alternatively, spell level 6 * CL 11 * 50 is 3300gp, which is probably fair as well.