can I send more than 1 steem ? What happens if I send 2 steem with one sponsored member in memo

You get two shares, and they get two shares.

why those 2 members (one has 17 shares, and the other have 68 shares, see in the comments) have the same vote value ?

Their posting frequency happens to have left them with the same rshares balance at the particular moment that they called the bot. The 68-share account will accrue new rshares four times as fast as the 17-share account, so they'll diverge quickly - depending on how often they "spend" their rshares balance by posting and receiving votes.

-Tim (SBI support)