Difference in the total stellar mass M_⋆ between STARLIGHT/FADO (out) and REBETIKO (in) values as a function of the CSP age t for different SFHs (see Cardoso et al. 2017 for more details), from left- to right-hand side and top to bottom: 3 exponentially declining (TAU1, TAU2 and TAU3), 1 continuous (CONT) and 5 delayed (DEL1, DEL2, DEL3, DEL4 and DEL5). Red and blue lines represent results with STARLIGHT and FADO, respectively. The black solid line represents the Hα EW value (see right-hand side ordinate) and black solid squares show the age coverage of the adopted base library Base .