Not really. Put yourself in the situation of both of the selling clubs. They obviously want to sell, their eyes are lit up that it's a PL Club that's after their player (the player will also be keen because it means they massively improve their personal salary - maybe it flushes out a player really keen on joining us, isn't it better to want a player that has the enthusiasm to make a difference here, or would we prefer a Perisec picking up the last big paycheck of his career who doesn't appear be want to be here at all?) so they know they can obtain the PL tax and that the money is there. BUT both the selling clubs know that the buying club (Spurs) can and are willing to pull the trigger on one of two players, they know that it's not bullshit either as both players are similarly profiled. Therefore they only have a 50% chance of cashing in on their player. Whilst it might not mean affect the valuation it lends itself to no fucking around by Club and agent with silly terms and small print guff, but most importantly it motivates the seller.
Should we opt to sign both it doesn't change that either as we appear to be advancing both deals close to a point of accord making that move possible. Should this be about signing just one then it won't change anything either.
Good sensible negotiating tactics by Spurs
Not to be forgotten is that Paratici was apparently 'famous' for negotiating with multiple players at any one time, but to be honest this is common in the commercial world - a tender process is an open and transparent process where multiple suppliers put forward their best prices/services in response to a specification put to all the suppliers at the same time