Let $ Pi_q $ be the projective plane of order $ q $, let $psi(m):=psi(L(K_m))$ the pseudoachromatic number of the complete line graph of order $ m $, let $ ain { 3,4,dots,tfrac{q}{2}+1 } $ and $ m_a=(q+1)^2-a $. In this paper, we improve the upper bound of $ psi(m) $ given by Araujo-Pardo et al. [J Graph Theory 66 (2011), 89--97] and Jamison [Discrete Math. 74 (1989), 99--115] in the following values: if $ xgeq 2 $ is an integer and $min {4x^2-x,dots,4x^2+3x-3}$ then $psi(m) leq 2x(m-x-1)$. On the other hand, if $ q $ is even and there exists $ Pi_q $ we give a complete edge-colouring of $ K_{m_a} $ with $(m_a-a)q$ colours. Moreover, using this colouring we extend the previous results for $a={-1,0,1,2}$ given by Araujo-Pardo et al. in [J Graph Theory 66 (2011), 89--97] and [Bol. Soc. Mat. Mex. (2014) 20:17--28] proving that $psi(m_a)=(m_a-a)q$ for $ ain {3,4,dots,leftlceil frac{1+sqrt{4q+9}}{2}rightrceil -1 } $.
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