Any coin that promises a 1000% ROI on an expensive masternode is a red flag for me. You have no idea what the Roi will be as it depends on the market price of Scriv.
ROI is the % of the MN required coins so you can calculate exactly what ROI will be, it doesn't have to do anything with the market price.
No, real ROI will depends on total number of masternode in the network at specific point of time; and price of Bitcoin.
Yes on MNs on the network but no on the price of BTC. ROI is calculated in terms of the coin itself.
Like in SCRIV case if 100k coins are required for MN 100% ROI would be to make 100k coins a year, 1000% ROI would be to make 1mil SCRIV a year.
masternodes.online shows you the comparison price in USD and BTC but not ROI. For example if you paid 1 BTC for 100k and ROI is 1000% it doesn't mean you will make 10 BTC a year. If in a year you have 1,000,000 SCRIV but 100k would be worth only 0.1 BTC your actual ROI would be 0%