UNkown functions on the bc72xlt

Theres a couple of things Ive come across with this scanner that the owners manual does not explain:
1) In the close call mode if the "hold" button is pressed on the bottom left the word 'hold' will appear with either the word Lo, Hi, Air, Or uhf above it, I can't figure out what this is for.
2) while in search mode SOmetimes to the right of the frequency number a smaller number will appear, usually a 25, 50, or 75. Cant figure out what this means