Presence of Mind is now a requirement on Sona, a 30 refund is not nearly enough for these new costs
Q: 75 / 80 / 85 / 90 / 95 MANA W: 105 / 110 / 115 / 120 / 125 MANA E: 90 MANA
The lowest total cost on these abilities is 270 with a POTENTIAL 90 Mana refund, potential basically meaning you're never once allowed to set a foot away from your ADC to poke/ward because there's no time to make it back to your ADC to get the refund. At max level these abilities cost a total of 310 with the same unchanging 90 Mana refund. And just a reminder, Sona's base Mana is 340.6 – 1105.6, and the only Mana item she ever tends to even build is a 
She starves herself so unforgivably fast with these new Mana costs, which all require multiple casts to provide meaningful returns mind you, and this results in Presence of Mind's Mana refund and 500 flat Mana-pool increase being a must for her to even operate now. I'm all for making it so she gets something for sticking by her carries instead of fighting solo, but she needs to actually get a reward for doing these things. That refund needs to either be changed to 30 per ally hit, or make it an even 50% refund after hitting an ally, because right now 90 potential mana is not nearly enough to make up for the absurd costs she's spending on such objectively weak abilities.
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These changes are obviously targeting sona top which is a troll pick anyways.
It is pretty easy to tag your adc with your aura bot lane as they last for a few seconds after you cast them.