Yes, its called 'draw'. You will find metal castings are the same and the draw often has to be more sloped the deeper a casting is to be to minimise any chance the pattern has to drag on the mould as it is removed with detrimental results.
The master is also a certain percent larger than the end product to take metal contraction into account when it cools. A plastic kit may not need to worry about shrinkage so much, though this can affect surface quality regarding the dimples you find in some kit parts? But draw is required to ease the removal of kit parts from the sprue aided by knock out pins which used to be put in plces where they could be seen on the kit requiring lots of sanding or filling and then sanding (Glee famine
) but then plastic kits used to be children's toys and only in the last thirty odd years have kit manufacturers realised that kits are more likely to be bought by adult enthusiasts and thus a move towards more careful design of kits and also their price increase majorly in 2007 when a Ģ25 tank kit suddenly rose to Ģ39-45
My then local kit stockist had a fit as his cashflow got seriously raided.