Additive model for IOV and IIV within a logit-transform

Dear NMusers, In a paper by Kerbusch, Wählby, Milligan, & Karlsson (BJCP 56 (6), 639-652) the authors state that: "The bioavailability (F) depended on the formulation (immediate = IR or extended = CR), the dose, and CYP2D6 genotype. Interindividual variation for FIR and FCR, and interoccasion variability for FIR and FCR were described using additive models within a logit-transform" and reported VARIABILITY ESTIMATE (CV) IIV F,IR 67% (20%) IIV F,CR 67% (20%) IOV F 37% (13%) Could a kind NMuser please provide the additive model for IOV and IIV within a logit-transform. MORE importantly, please elucidate the formula for computing the variability estimate of IIV and IOV in F. The table footer states "F: bioavailability centred at median dose". Does this mean that the reported variability estimate is only relevant at the computed F value for the median dose? Thanking you in advance...MNS