ALV OM Header / Footer alignment

The class for controlling alignment in the header/footer is cl_salv_form_layout_data_grid.

Example:
data: lr_grid type ref to cl_salv_form_layout_grid,
lr_layout_grid type ref to cl_salv_form_layout_data_grid,
lr_label type ref to cl_salv_form_label.

lr_label = lr_grid->create_label(
row = 1
column = 1
colspan = 4
text = 'Net Profit Report'(h01)
tooltip = text-h01 ).

lr_layout_grid ?= lr_label->get_layout_data( ).
lr_layout_grid->set_h_align( if_salv_form_c_h_align=>center ).