There are 2 possibilities as to why the aerosol Matte Black would’ve come out a little shinier than the gallon cans – (1) Majic Tractor, Truck & Implement Paints are high solids coatings – couple that fact with Matte Black & Primers are also very heavily pigmented. Unfortunately, this sometimes results with settlement in the bottom of the can… The pigments in this settlement determines the sheen level of the finish product. If this settlement is not thoroughly mixed back into suspension (sometimes requiring shaking for 3-4 minutes, by hand), there is not enough pigment to absorb the resin and produce the desired matte finish… the second (2), and more likely possibility is Matte finishes are relatively slow to develop. If a Matte finish was applied last weekend…then touched up with an aerosol the next weekend (example), undoubtedly, the applied aerosol finish would appear shinier – at least for a few days, but it will reach the specified sheen in time. A Matte finish may take as long as 2 weeks to drop down to the sheen level as specified