Source Arcane Anthology pg. 31
This collection of brooding poetry, all in pentatonic verse, expresses Arrowsong’s frustration over her overbearing parents’ desire for her to become a spellcaster. Her in-depth analysis of their struggles and failings provides great insight into reading and memorizing spells from a spellbook.
Prerequisite: Perform (oratory) 3 ranks.
Cost: Feat or 1st-level spell known or higher (see text).
Effect: Rather than a single work, this masterpiece is a collection of poems from Arrowsong’s days living under her scholarly parents, who both desperately wanted their daughter to pursue the art of wizardry. Despite the poems’ wry tone and the overall distaste for book-learning they proclaim, Arrowsong’s verse perfectly documents the process of memorizing arcane spells. When you gain this masterpiece, it becomes associated with your bard spells of a specific spell level. If you paid the masterpiece’s cost by spending a bard spell you know, the masterpiece is associated with spells of the spent spell’s level. If you paid the masterpiece’s cost by spending a feat, you choose one bard spell level that you are able to cast with which to associate the masterpiece.
In order to perform this masterpiece, you must be holding a spellbook, scroll, or a similar piece of arcane writing to consult. After completing the masterpiece, choose one arcane spell from your bard spell list or from the sorcerer/wizard spell list that is written on the arcane writing that you consulted during the masterpiece. If the spell is on your bard spell list, it must be of the same level (or lower) as the spell level associated with this masterpiece. If the spell is not on your bard spell list, its level must be at least 2 spell levels lower than the spell level associated with this masterpiece. Add the chosen spell to the bard spell list and to your list of bard spells known until the next time that you rest and regain spells.
If you use a spellbook with a preparation ritual to perform the masterpiece, you also gain the boon associated with that spellbook, as if you had prepared a spell from it. You can add up to one spell per spell level that you have selected with this masterpiece to your list of bard spells known each day. You can gain this masterpiece multiple times. Each time, you must apply it to a different bard spell level.
Use: 3 rounds of bardic performance per level of the spell.
Action: 1 hour of meditation.
If my Bard used this Masterpiece to learn a 1rst lvl Wizard spell he would need to sacrifice a 3rd lvl Bard spell known. Would casting that 1rst lvl Wizard spell use a Bard 1rst lvl spell slot or a 3rd?
Costing 3 or 9 rounds of Bardic Performance?
That's how I interpret it as well. I just wanted some other opinions to see if I was on the right track.