  This paper proceeds an approximate calculation of ultimate time survival
probability for bi-seasonal discrete time risk model when premium rate equals
two. The same model with income rate equal to one was investigated in 2014 by
Damarackas and \v{S}iaulys. In general, discrete time and related risk models
deal with possibility for a certain version of random walk to hit a certain
threshold at least once in time. In this research, the mentioned threshold is
the line $u+2t$ and random walk consists from two interchangeably occurring
independent but not necessarily identically distributed random variables. Most
of proved theoretical statements are illustrated via numerical calculations.
Also, there are raised a couple of conjectures on a certain recurrent
determinants non-vanishing.
