Impedance control with FR4-Standard TG 135-140

When selecting 4 or 6 layer boards, the quote page selects "FR4-Standard TG 135-140" as the default dielectric material, even when impedance control is selected. However, your documentation for the impedance calculator states that an NP-155F dielectric material is assumed, which presumably matches the "FR-4 TG155" option on the quote page.

When impedance control is selected, are traces adjusted for the Tg135-140 material, or is the incorrect impedance simply accepted and manufactured as-is? (If the impedance will be incorrect, it would be very helpful to have the quote system warn users about this and ask if they want to switch to Tg155!)

Can you provide specifications (Dk, Df, etc.) for the material used for Tg135-140 boards? A datasheet would also be helpful. Thanks.