Congruence speed of tetration bases ending with \(0\)

For every non-negative integer \(a\) and positive integer \(b\), the congruence speed of the tetration \(^{b}a\) is the difference between the number of the rightmost digits of \(^{b}a\) that are the same as those of \(^{b+1}a\) and the number of the rightmost digits of \(^{b-1}a\) that are the same as those of \(^{b}a\). In the decimal numeral system, if the given base \(a\) is not a multiple of \(10\), as \(b := b(a)\) becomes sufficiently large, we know that the value of the congruence speed does not depend on \(b\) anymore, otherwise the number of the new rightmost zeros of \(^{b}a\) drastically increases for any unit increment of \(b\) and, for this reason, we have not previously described the congruence speed of \(a\) when it is a multiple of \(10\). This short note fills the gap by giving the formula for the congruence speed of the mentioned values of \(a\) at any given height of the hyperexponent.