A method for controlling regeneration within an after-treatment component of a compression-ignition engine comprises calculating an initial estimate of accumulated particulate matter based on a pressure-based soot accumulation model and a pressure drop index indicative of a decrease in pressure across the component. An adjusted estimate of accumulated particulate matter in the component is calculated based on the initial estimate and a soot prediction error inherent in the soot model. The adjusted estimate is compared to a predetermined threshold associated with the after-treatment component, and a remedial action is initiated when the adjusted estimate of accumulated particulate matter in the after-treatment component exceeds the predetermined threshold. The pressure-based soot accumulation model may be configured to predict soot accumulation in the absence of passive regeneration, and an adjusted kinetic burn model may be used to estimate a quantity of soot disposed through passive regeneration.