there is no way to make profit from spread change on the same data feed.
you pay spread when you open on long
you pay spread when you close on short
ask side is the pay spread side.
when you go long @1.0000 your profit/loss will be calculated from the Bid.
as soon as you open the trade you will be in loss as much as the spread.
first, bid should reach the ask price to BE ( break even )
'If you close, you gain 10pip.'
you open long with 'ask' and will close it with 'bid'. not with 'ask'. so there is no profit when spread changes.
is that clear?
Let's suppose the current bid/ask is
spread = 10pip
and you long @ 1.0000.
If this changes to
spread = 20pip
If you close, you gain 10pip.
So, widen spread doesn't necessarily mean you lose...